Periodic Tales
by sevenpercent
Summary: As a chemist, Sherlock uses the Periodic Table for many reasons. A collection of short fics that add up to a better understanding of what he is and how he reacts to the catalysts in this life. Polonium Part One now up
1. Chapter 1

**Periodic Tales**

**Summary: As a chemist, Sherlock uses the Periodic Table for many reasons. A collection of short fics that add up to a better understanding of what he is and how he reacts to the catalysts in this life.**

**Elementary **

_Pertaining to or dealing with elements or first principles. Of the nature of an ultimate constituent, pure, simple, uncompounded. Pertaining to the four elements (earth, water, air and fire); chemistry of or noting one or more elements._

It was one of those rare occasions when John went into Sherlock's bedroom. He tried to respect his flatmate's right to privacy, in the vain hope that he might reciprocate. But, Sherlock's idea of sharing a flat was taken literally, as in everything of John's that was in the flat was therefore available for Sherlock to use.

But, on one of John's occasional mid-week days off, he had decided to do the crossword in the newspaper, and one of the clues was the "a Noble 18". He thought it might be an entry on the periodic table, and he knew exactly where to look for that one. Sherlock had a framed version of the table on his bedroom wall. So, John walked in and found Number 18 was Argon, a Noble Gas. _Whatever the hell that is compared to a 'normal' gas._ He chuckled; Sherlock could no doubt pontificate on the subject in his public school accent, without realising the aristocratic irony.

Later that afternoon, Sherlock returned from investigating an art theft at a Knightsbridge Gallery. Over supper, he recounted how the case had been solved.

"Really interesting, John; the painting was stolen by the artist himself. Turned out to be a forgery, being sold as the real thing, and he had an attack of conscience- but made it look like a robbery, so the gallery owner could collect on the insurance."

John tended not to accompany Sherlock on art theft cases- not much use for a medical opinion without a body involved. He felt even more like a useless appendage than usual. Another reason was that Detective Inspector Reynolds, in charge of the Met's Antiques and Art Unit, didn't like 'extraneous personnel' on a case. He barely agreed to accept Sherlock's help, but that was more often than not at the special request of the gallery, museum or art owner involved.

So, over a cup of tea, Sherlock finished regaling John with the tale of how the forged painting was discovered under freshly applied gesso in the painter's studio. As ever, John was impressed with the consulting detective's grasp of art, painting techniques and the chemistry needed to know how to remove the gesso without destroying the painting underneath.

"Sherlock, speaking of paintings, why do you have a framed version of the periodic table on your bedroom wall? I mean, it's pretty pointless. You know the data on it backwards and forwards, being a chemist and all. It's not even 'art'. So why hang it up on a wall?"

Sherlock went quiet for a moment. The animation that had accompanied his talk about the case went out of his eyes, and he looked down at the floor. John was surprised; somehow the question had made Sherlock uncomfortable.

After a minute of silence passed, John gave up waiting. He shrugged his shoulders and went into the kitchen to do the dishes from supper. He'd managed to interest Sherlock in eating (_Case is over, John, so I can indulge._) As he washed up, he shook his head. Only in Sherlock's head could a normal meal be considered an indulgence. There was so much he didn't understand about his flatmate.

When he came back into the living room and picked up his book from his chair, Sherlock was staring into the fire, his face just looked blank. Three pages into the thriller's story, Sherlock spoke in a subdued tone.

"It isn't a painting, John; it's a print. Of course, I know the periodic table. It's there to remind me of the times in my life when I need to remember it."

John looked over at his friend, hearing the tentative tone and the uncertainty. He put his book down. "I'm not sure I follow- does that mean it somehow gets deleted?"

"No, of course not, it's the one constant- in fact, that's why I need to remember it. When things get …too much. Noise, people, Mycroft, just too much to take in, I need to find a way to shut it all out. So, I start with the periodic table, each element, in order, the atomic weight, the orbits, at what temperature the element will be a solid, liquid and gas- did you know that mercury is the only naturally found element that is a liquid at room temperature? Bromine can be pushed to become liquid at that temperature, but not naturally."

John was used to these little asides- it was as if tangential data just created a little dam in his normal flow of conversation. Without pausing for breath, Sherlock carried on. "I learned the significant compounds related to each of the 118 elements, when they were discovered, and how they are used- it's data, John, hard ordered facts. They ground me, remind me that everything is understandable through chemistry and physics. Going through it all makes me feel safe and in control. There are no lies. Isotopes, allotropes, half-lives- all so… so perfect in its order. It taught me that everything is part of everything else; that nothing dies. It just changes."

Then, almost in a whisper, he said "I need that." Sherlock was looking down at the fire, and the light cast by the flames made his eyes glitter.

John thought about the process. "I've heard of people using mathematics for that kind of…" he couldn't think of a word. 'Therapy' was wrong. But he wasn't a psychiatrist, so he struggled to think of a phrase that would not offend his friend.

Sherlock didn't wait for him to finish the sentence. "When I was little, Mycroft tried to get me to use maths and equations to distract myself. _He_ used to drive me to distraction- I couldn't explain what I needed, but it wasn't sitting there calculating the value of pi to 23 decimal places." He waved a dismissive hand, "Maths is just a means to an end."

"Chemistry is …elegant. It is aesthetically pleasing. So much more detail. And…" here he gave a tiny smirk, "Maths can't explode. Chemistry can."

John smiled. That was Sherlock in a nutshell. Needing to feel safe, yet thrilled by explosions- an enigma, a combination of contradictory elements never quite in a stable state. _I'm never bored._


	2. Chapter 2

**Author's Note: ** we get underway with Periodic Tales, so a word about how they will be structured. Each element forms an arc, but they do accumulate over time. When there are multiple chapters under each element, I will identify them by allotrope or isotope- or maybe their use/application.

* * *

**Hydrogen H 1.00794**

_The first element on the Periodic Table. Discovered in 1766. Its name means "water-former". The lightest element and the most abundant, it constitutes 75% of the mass of the universe. It is the stuff of stars, the catalyst of bombs and the beginning of everything. _

**Part One: H(1) also called Protium; atomic Hydrogen is the most common form of hydrogen. It has one proton and no neutrons.**

* * *

The relief nurse looked at the young boy. She was new to this ward, only started this week. She would be providing maternity cover for the night nurse, who was talking her through her charges. This boy had been in care now for eighteen weeks, originally admitted for depression following the death of his mother ten days after his tenth birthday. He had been also diagnosed as emotional labile, developmentally damaged and experiencing communication regression. He had not spoken once while at the hospital, and his anti-social behaviours had become exaggerated during his time in care, so the diagnosis was not encouraging. The usual round of anti-depressants and other drugs to treat his symptoms were having limited effect. Actually, in some case, the effects had been paradoxical. That had led the psychiatrist down an unorthodox route, which was beginning to have some benefits. At least, he'd stopped crying all of the time.

Angela, the night nurse continued her description, "He doesn't sleep properly, I am afraid. Epileptiform at Dream stage IV, so is awake at odd times in the night. Hasn't seized yet, but who knows when it might start. When he gets anxious, I've taken to reading from the book he keeps with him all the time. It seems to calm him down."

She looked at it on the bedside table. It was called _Building Blocks of the Universe,_ by Isaac Asimov. _Wasn't he a science fiction writer? _They went on to the next bed- a little girl with cerebral palsy who had broken her leg quite severely, and Angela started giving her the details.

oOo

"How did you first get interested in the periodic table? Did you learn it in school?" John tried to remember when he'd first come across it- probably when he started at the local comprehensive school. He'd not thought much of it at the time; he was more interested in biology, but that might have been because he was lab partners with Caroline Jones, whose giggle he found positively infectious when he was thirteen and a half.

"My mother gave a book about the periodic table for my tenth birthday. And I read it over, and over, until I knew everything that was in the book. I decided to become a scientist then."

"I thought you wanted to be a pirate when you were young." John had heard that from Mycroft. Sherlock did not answer; he seemed lost in thought.

* * *

**Author's Note:** a request! When you spot a typo (and hey we're all human) or a chemistry issue- do me a favour and use a PM to tell me. Why? Because if you stick it in a review, once I fix it (and I almost always do) the comment becomes redundant. I like keeping reviews about content; it helps readers (and ME!) so please do keep reviewing.


	3. Chapter 3

**Hydrogen Part Two**

**H(2) Molecular Hydrogen, also known as Deuterium, the second isotope when combined with oxygen through combustion yields the water.**

* * *

It was Nurse Anne Lowery's third night shift, and it wasn't going well. The boy was shouting and he had woken up several of the others on the ward, who were now in a right state. She had tried to get him to identify what it was that was bothering him. _But when you can't or won't speak, that's not easy. _ She'd tried to talk soothingly to him, even tried a lullaby. When they woke up in unfamiliar surroundings and in pain, a calming voice and a maternal kind of sympathy often helped to steady them; it usually put the little ones back to sleep.

Not this boy. She'd learned the names of her ward charges quickly, and his stood out as one of the oddest. _Sherlock – his parents should have known better; he'll be bullied about his name for years._ Mind you, he wasn't responding at all to her use of it. He wasn't shouting words; not screaming, just noises. He didn't appear to be in pain, just really angry and thrashing about. She'd realised as soon as she touched him that it only seemed to make matters worse, so she let go. She went back to the nurses' station and put a call into the duty doctor. "I need some sedation down here; the Holmes boy is just freaking out." He said he'd be down as soon as he could, but there was an urgent case of appendicitis that took priority.

She went back to his bed where the boy was now rocking violently, making the metal bars along the left side smack into the wall with a bang every time he threw his weight against it. That's when she spotted the book on the bedside cabinet. What was it Angela had said? She'd read to him to calm him down. She pulled up a chair and opened the book. To her surprise, it wasn't fiction; it was a science book.

She opened to the first page and started to read, "_When scientists talk of matter, they mean anything at all that has weight- a rock, a human being, a book a pail of sea water, or an automobile, Almost anything else you can name, including the sun, the moon, and the stars, is matter…_

By the time she had reached the end of the introduction's four pages, the rocking had stopped. As she turned over the page, she took a stealthy look at him. He was listening. Not looking, no- this one did not ever make eye contact. But, he was staring at the ceiling as if not seeing it, but something else. _Or someone else? _She knew that his mother had been his principal carer and that she had died recently of pancreatic cancer.

"_Hydrogen was given its modern name by Lavoisier who called it after the Greek words meaning ' giving rise to water'."_

She looked over again, and saw that Sherlock's face was wet with tears.

oOo

After months of living with Sherlock, John's own powers of observation improved dramatically. He had learned, for example, the measure and character of Sherlock's mood simply by the nature of the chemistry experiments he performed. There were those conducted intensely but quickly- these generally related to an active case, where he needed an answer quickly, in order to prove or disprove one or more of his working theories. Be it an exercise of finding out how long it took for stomach acid to breakdown a particular piece of candy or learning how quickly bruises would emerge on an already dead cadaver- these were usually undertaken at speed and with an intensity bordering on fanatical. John knew better than to interrupt at any point. Indeed, he'd even been roped into a few.

"John. Please provide a urine sample, a man's life depends on it_._" A hand with a glass beaker appeared in front of john's chest, but Sherlock's head did not lift from the microscope.

John frowned. He was on his way from the kitchen to his chair to drink a cup of tea he'd just made. "Why don't you do it? What's wrong with _your_ pee?"

"I'm not the one drinking six cups of tea a day; you must have volume to spare."

When John headed off to the bathroom, Sherlock's baritone followed him- "Make it a mid-stream clean catch please!" John muttered as he obliged, "I do know basic testing procedures, thank you very much."

When the doctor came back from the bathroom carrying the beaker, he asked "What are you going to do with it?"

"I will heat it to drive off the water and examine what remains." He looked bemused. The one John had provided was a light yellow, but there was another one on the table that was much darker, in a standard medical sample bottle.

John's forehead creased. "Is that someone _else's_ pee?"

"Yes- my client's." It turned out that the victim of the attempted murder had given a medical sample about an hour before he fell ill. "Clearly, he doesn't drink as much tea in a day as you do." Sherlock smirked. "Human urine is usually 95% water, with organic solutes including urea, creatinine, uric acid, and trace amounts of enzymes, carbohydrates, hormones, fatty acids and mucins; then there's the inorganic ions- sodium, chloride, magnesium, calcium, ammonium, sulfates and phosphates. But I'm after the potassium content, because I think someone gave him a lethal dose and caused the heart attack that nearly killed him."

He poured the John's beaker into the flask, and lit the burner. "Yours should show a concentration of about three quarters of a gram of potassium per litre. Once I isolate the potassium in his sample, then I can also see if there is a contaminant in there with it which will give a clue as to how it was ingested."

John smiled. "Whatever keeps a client alive and you happy, Sherlock."

oOo

He was less amused when he watched some of his possessions disappear, as experimental material.

"John, it was necessary to see how fast your wool jumper caught fire compared to that acrylic sweater Harry gave you, which you hate and have never worn; the rate of combustion determined which brother was the killer."

"But that wool sweater was my _favourite._"

"Sometimes sacrifices need to be made for the good of society." He smirked, knowing full well what was about to come in reply. _Three...two...one..._

"Yeah, as if you cared about that," followed by a long suffering sigh.

Then there were the more sedate experiments- usually conducted on some body part dragged home from Barts, courtesy of Molly, on which various odd tests were performed. Bags of thumbs, jars of eyeballs, Tupperware boxes of gall bladders took up space in the fridge and kept him busy when the case work dried up. Sherlock wrote up results and posted them on his blog, or occasionally in some publication or another, such as _Forensic Science International_ or _Journal of Forensic and Legal Medicine_. These were worthy exercises and kept Sherlock occupied for hours as he tested and re-tested to get statistically significant findings that would hold up under academic peer scrutiny. Excruciatingly dull in John's eyes, but, hey- if it kept the mad scientist busy and out of trouble, then it was fine by the doctor.

"Sherlock , you're going to get curvature of the spine from bending over your microscope for so long. You realise that you've been at that same experiment for the past seven hours?"

"Time flies when you're having fun."

OoO

Time doesn't move when you're in hospital. The boy had lost all sense of time. He knew he arrived one week, three days and twelve hours after he was told his mother died. But, he no longer had any idea how many weeks, days, hours, minutes and seconds had passed since then. That made him anxious, because sometimes he liked counting the time and knowing what was supposed to happen at each moment. It made him feel safe. He didn't feel safe here. It was strange.

Mycroft was the one who told him that mummy died. His father didn't. He must have known, because Mycroft said mummy died on Sunday. His brother told him this on Tuesday. So father had been home in the house with Sherlock for two days and not told him. He hadn't spoken to him at all during that time, and Sherlock was glad. He didn't like Father. He made him feel anxious and then he made mistakes, and they both got angry. Sherlock had developed an innate sense of knowing just where his father was going to be in the house, and avoiding that place.

oOo

"When?"

Mycroft looked at his brother, who wouldn't look him in the eye. He thought that telling Sherlock about mummy's death was perhaps the hardest thing he'd ever done in his seventeen years. He was angry that his father made him be the one to tell Sherlock, but he also understood why. "The boy never speaks to me; at least he talks _at_ you." And he knew that his father blamed Sherlock in some way for exhausting their mother in her final months. So, he agreed to tell his brother.

"On Sunday, at the hospital. She passed away in her sleep. She was on morphine, so not in any pain."

Sherlock flapped his hand. "When, _exactly_."

"2.58am." He wondered about his brother's need for precision. Time mattered to him in ways that Mycroft didn't quite understand. Sometimes he had to know exactly; other times, he didn't even know what day of the week it was.

"Who will read with me now?"

It was so matter-of-fact that it just took Mycroft a moment to process. "Sherlock, do you understand that Mummy won't be coming back?"

"Yes, of course. She's dead. When things die, they don't come back. No matter what the vicar says on Sundays."

"The funeral will be held in four days' time."

"On Saturday."

"Yes. We need the time to let all the family and friends know so they can attend."

"Why?"

"Do you mean why are we holding a funeral? You _know_ what a funeral is; we all went to Aunt Ingri's last year, in Oslo, remember?

"No, why are _they_ attending?"

"Because people want to pay their last respects."

"What does that mean?"

"People who loved mummy want to celebrate her life and say goodbye, to share their grief."

"I don't understand."

Mycroft just looked very sad and blinked away the tears. He'd promised his mother that he would be strong for Sherlock.


	4. Chapter 4

**Hydrogen Part Three **

**H(3)** **Tritium, the third isotope of Hydrogen**. **With one proton and two neutrons, it is radioactive and a by-product released as a result of the destructive power of nuclear weapons tests. **

* * *

Mycroft's heavy footsteps could be heard as he walked down the seventeen steps back to the front door. Sherlock's face was set like stone, and the air positively crackled with supressed rage. John had just witnessed an argument of toxic violence dressed up in the polite words exchanged between two adults who both want to hurt one another, but who are also beyond punching each other out.

"Why do you two get on so badly, Sherlock?" John just frowned. "I get the feeling that there is a lot of history between the two of you, and I'm not prying, but…Jeez, you two ought to issue an alert that a bomb's about to go off when you really get going. With some warning, I'd head for the bunker and get out of the blast radius if I knew what was coming."

Sherlock moved his glare from the doorway to John's face. "You and Harry aren't exactly 'best mates', so why do you assume I should get on with that fat git?"

John wondered if Sherlock was right. Was he being fair? He and Harry had fought like cats and dogs when they were kids, and when their parents were gone, and she started hitting the bottle, their arguments had escalated. Was the level of animosity between the Holmes brothers any worse?

"Actually, I'm no saint here, but there is a difference of degree in what you and Mycroft throw at each other that makes it truly awful. I guess as kids Harry and me didn't get on, and as adults we fight dirty with words, when hair pulling and pinching used to be enough. But…you two? Well, you elevate a family dispute into a thermonuclear war. Harry and me chuck grenades; you and Mycroft slug it out with hydrogen bombs. Someone's going to get hurt."

Sherlock looked at his flatmate in surprise. "Whatever gave you the impression that we didn't want to hurt each other?"

oOo

The day before the funeral, the house started to fill up with family and friends. A woman arrived and was introduced to Sherlock by his father. "She's here to look after you." Just being in the room with his father made him nervous, and he wouldn't look at the woman's face. He didn't know her; he didn't like new people. They frightened him. She smelled funny.

That night he had a seizure- just a mild one, he didn't even wet the bed. But the strange woman came in and turned on the light, which made him scream, and then curl up in a ball. She was talking at him, but he ignored her and then he felt his face was wet and he'd started to cry. The whimpers turned into sobs, and then into gasps as he couldn't seem to catch his breath, and that made him even more frightened, so he kept crying. Once he got started, he didn't know how to stop.

Mycroft heard the noise and came in, told the nurse to go away, and turned off the light. He sat in the chair by the bed. "I'm here, Sherlock. Just try to do this quietly, or father will wake up." The little boy's sobs seemed to diminish in volume, but they didn't stop. Listening to his brother finally broke the dam that had held Mycroft's own emotions in check, and the sound of his own crying merged with that of his brother.

He'd been strong until then. When he'd taken his mother's call in the first week of November and she asked him to meet her in London for tea, he'd been pleased at the opportunity to see her. It was his first term at Balliol College and he was finding Oxford to be everything that he had hoped it would be. His weekly one-to-one tutorial sessions with some of the most distinguished academics were stretching his mind, pushing him to new levels of understanding. The PPE* degree was _so_ interesting; the lectures might be a bit boring as he already knew most of what they covered, but he'd joined the Oxford Union straight away and was enjoying the debates immensely. There were so many interesting things going on. He was meeting a lot of new people, making contacts who he knew would be useful later on.

He'd spent the hour long train ride from Oxford to Paddington Station thinking about what he'd tell his mother about his first term. That all changed the moment he laid eyes on her in the Palm Court at the Langham Hotel on Great Portland Street. She looked ill and exhausted, but when she saw him her face lit up with a wonderful smile.

"Hello, darling. Give me a kiss, and then sit here. I've ordered you a lunch. I hope you won't mind eating it on your own, but I'm just not hungry at the moment."

She asked him about Oxford, and he tried to tell her as he tucked into his lunch, but the enthusiasm he'd had on the train waned. _What is it she's not telling me? Maybe Father's finally asked for a divorce? _

So Mycroft asked when Father was planning on getting back from his latest business trip to the Far East, as a way of giving her a chance to introduce the subject.

"Oh, it won't be for another couple of weeks. He's working so hard right now on that pharmaceutical factory project in Singapore, I know he wants to finish it so he won't have to go back before Christmas."

He picked at his lunch as he waited for her to tell him what was wrong. He was worrying now that maybe something had happened to Sherlock, so he actually missed the first part of what she said once his plate was cleared away. Then his brain caught up,"… had a few tests done and I'm so sorry to have to tell you that the doctors say it is inoperable pancreatic cancer."

His face must have betrayed his horror. She looked at him gently. "Now Mycroft, I know that it's a bit of a shock, but you're old enough to cope with this without making a scene in public."

He tried to concentrate on not losing his lunch, embarrassing himself and his mother. He struggled to find some words. "Does Father know?" _No, of course not; despite his affairs, he'd be on the next plane if he knew; why did I ask that? Stupid!_

She just looked at him.

Mycroft blushed at his own stupidity. "Of course, not. You want him to finish this…work so he can be home for an extended period."

She reached across the table and put her hand over his. "It won't be _that_ extended, my dear. The doctors say it will happen very quickly. I shall be lucky to spend Christmas with you all. That's my goal anyway."

He looked away from the table for a moment and watched the other people eating their lunches. Happy people, families, couples, even a few people on their own- none of whom were dealing with what he was trying to understand. A nuclear explosion had just gone off in his life. _My mother is dying._ Then he stifled a noise erupting from him, closed his eyes and tried to get a grip.

When he opened them, he looked into her blue eyes. _Everyone has always said that I take after father, except that my eyes are like hers_.

"Surely there must be treatments- chemotherapy, drugs... You need to tell Father; his companies must have some experimental protocols, something that hasn't been released yet. You have to tell him _now_ so he can find something." He realised his voice was breaking and he was losing control of his breathing.

"I'm so sorry Mycroft. I know this is awful for you. It's no good. The doctors can only offer palliative care; something to ease the pain when it gets really bad. But it's too late. I'm already in Stage Four and it's metastasising like mad, apparently- already in my gall bladder and liver. The surprising thing is that I haven't actually felt terrible for more than a couple of weeks- just thought I'd strained my back…" That's when Mycroft realised why she might have thought that; she was the only one that his brother allowed to touch him, to pick him up.

"Oh God, Mummy- does Sherlock know?"

This was the first time that her own eyes betrayed her, and she looked down at their hands on the table. Quietly, she said "No. Oh, he knows I've been tired and unwell, but doesn't understand why. And I'm not going to tell him, nor are you, and your father won't either, if I have any say in it. I want to be able to enjoy this last Christmas without having him distressed. He's made so much progress, really. You will be so pleased when you see him again."

"I'm coming home with you now. I don't want to go back to Oxford. I can suspend my studies for a year. It's not too late to do that."

"No, I won't have you looking at me the way you are right now, darling. I don't think I can cope with the idea of watching you watching me go downhill. It will be hard enough to deal with Sherlock. With you at home, he'd know something is wrong. You're not _that_ good an actor, Mycroft, and he is amazingly perceptive at times, you know that. And, anyway, you are doing so well at Balliol, I won't let this stop you. You'll just have to be strong. You can come home for some weekends, if you really want to, but it's only another six weeks until the Christmas break anyway. We can talk on the phone, if you'd like, every day, if that's important to you."

_If that's important to me…every moment you have left is important to me; don't you realise that? _He didn't feel at all grown up. He wanted nothing more than to run out of the room, hide himself in the gents and cry his eyes out. If he'd been anywhere other than in a public place…. _Of course, that's why she decided to tell me here. So I wouldn't do that. She wants me to be brave. _

He drew a deep breath and set his face. "Mummy, I'll try to do whatever you need me to do."

That brought a smile to her face. "Thank you, Mycroft; I really, really need this from you. I think neither your father nor your brother will be able to handle this well. You and I – we'll talk –lots- there are so many things that need to get sorted, and I will need your help."

* * *

**Author's Note:**

*PPE degree is a BA (Honours) programme unique to Oxford and the letters stand for Politics, Philosophy and Economics. Balliol College is renowned for its politics faculty and has three UK Prime Ministers and countless numbers of civil servants amongst its alumni.


	5. Chapter 5

**Oxygen O 15.9994**

_The eighth element on the Periodic Table. Discovered in 1773 in Sweden and 1774 in Wiltshire. T__he__ third most abundant element in the universe and the most abundant element in the Earth's crust, as well as in the human body. Essential for almost all forms of life on Earth, it is also highly flammable. It sustains combustion and, under pressure, can be explosive._

* * *

**Part One: **

**O(1 ) Atomic Oxygen – a free radical, which ****when generated in excess or not appropriately controlled can wreak havoc on a broad range of macromolecules. With extremely high chemical reactivity, it drives not only normal biological activities, but can inflict damage on cells.**

* * *

There was another kind of experiment that told John the depths of boredom, ennui and frustration into which Sherlock had fallen. Most, but not all of these, involved something explosive. Within a month of moving into Baker Street he'd bought new fire extinguishers and installed a smoke alarm.

He was upstairs getting dressed after a shower the first time the alarm went off. The noise was deafening, and Sherlock's shouting didn't help either. Mind you, for someone who was hypersensitive, at least Sherlock wasn't curled up in a ball in a corner with his hands over his ears. John managed to talk Sherlock off the kitchen table where he was standing trying to rip it out of the ceiling. John then got the ladder and pulled the battery out.

"That is the invention of the devil, John, and you will remove it immediately." Sherlock was almost panting, quite near to a meltdown.

"I can't do that, Sherlock, if you insist on trying to burn things and cause explosions in our kitchen."

But John did move the smoke alarm to the living room ceiling over the sofa, to give a little more leeway. He did buy another, larger fire extinguisher for the kitchen, and a fire blanket.

Today was the ninth day without a case. Mycroft often worried about 'danger nights', when Sherlock might be having issues, but in John's experience, he worried more about days like these. He could live with mad scientist, but bad scientist was...scary.

Sherlock had cleared the kitchen table of glassware and the usual jumble of kit. There was a small tin of something called Danish Oil, a rag and a canister of something John recognised as O+, which had been advertised recently on the TV as "recreational Oxygen" to "restore, revive, refresh- no calories, no carbs, no caffeine, no crash". His forehead creased. What the hell did Sherlock have in mind?

"Relax, John. Oxygen does not burn."

"Then why are you planning to start a fire with it?"

"I'm not. Oxygen, however, is needed for other things to burn. I am attempting to discover at what concentration level a mixture of oxygen and this oil will spontaneously ignite."

"Why?"

"Why not?" The glower that accompanied this very rhetorical question made it clear that any interference from John would be resisted.

oOo

"Ow!" The boy dropped the burning match. He had stolen the box of matches from the gardener who had left them in the pocket of his jacket, on the nail in the potting shed. Sherlock was hiding now in a lean-to that was attached to the mower shed. He was trying to light a candle so he could continue to read his biology book, but the wick was broken or damp, and the match had burned down to his fingers before it could catch.

The lean-to was a strange place, full of tins of odd smelling chemicals, pesticides, oils for the machinery, wood stains for the garden furniture. Sherlock recognised some of them- the fertiliser that his mother used for her tomatoes was in a bright red plastic bottle that had faded with age. He had not eaten a home-grown tomato this year. Mummy had been ill with flu in the spring, and then again in August, so she'd given up the vegetable gardening, resorting instead to just issuing instructions about the flower beds and the lawns.

"Keep James company, Sherlock; I need to rest for a while."

He didn't like James. The young gardener had no time for Sherlock. He just ignored the nine year old boy. "Piss off, will ya? I have work to do." His mother always tried to involve him in the process and would explain what she was doing as she worked. "The compost we made last year is now just the right thing for mulching. It keeps the weeds down and ensures the soil underneath doesn't dry out too much. Plants do best when they are kept just moist- not too much rain, and no prolonged drought."

He enjoyed the sound of her talking. He always listened, even if he rarely responded. He liked watching the bees and the other insects come to the flowers. He would ask the occasional question, like when she put a handful of brown powder under the roses. It came from a box with the words_ blood_, _fish_ and _bone_ on it. "Why are you putting it on the bush, Mummy? Plants are not carnivores."

He'd just learned about the different types of animal species, and was trying to figure out a puzzle his mummy had set him. "There is one class of mammal on the estate that is a true omnivore. You have until Saturday to figure it out." He'd spent lots of time watching the horses, actually tried to feed one a dog biscuit, but it had turned away. Nor could he interest the barn cats in left over vegetables. They drank milk, though, and that led him to read about whether dairy products were meat or vegetables. The answer, "neither" perplexed him. Did that make mammals into carnivores, herbivores and milkivores? No, apparently lots of mammals consume milk when they are babies, so that didn't count. The ducks would take bread, but not the salami that he'd put in his pocket when no one was looking when he ate lunch at the kitchen table with Mrs Walters, the housekeeper. The nearest he'd got was with the gamekeeper's dogs. They would eat pretty much anything, being Labradors, although one spat out an olive. The other one ate it, and Sherlock wondered what that meant, when a sample of two did the opposite from one another. But the Spaniels were more fussy, and ignored the vegetables. He'd looked it up in the encyclopaedia and discovered that dogs were classed as carnivores, but were opportunistic when fed something else. So, not the right answer.

Things were boring up at the house. His father had telephoned to say he wouldn't be home that night. That cheered up Sherlock immensely, but his mother had just sighed. "Right, Walters. I'm going to have an early night then. Just send a tray up to my room, could you?" When the housekeeper left, Mummy turned to Sherlock and ruffled his hair. She was the only one he let do that. He held his right hand out, fingers extended, and she put her larger hand to his so that their fingertips touched briefly. It was Sherlock's version of a hug. He didn't like to be held (_Too much touch, Mummy_) so they had evolved this way of showing affection. "Try to stay out of mischief, young man. I hope to feel better in the morning and we can tackle that iris bed. The perennials need dividing, and now's the right time to do it, before autumn frosts start."

He smiled at her, and went to get his biology book. He needed more research about what an omnivore might be. When Mrs Walters came up at nine o'clock, she told him to get ready for bed. "You need to _try_ to sleep, Sherlock, so put the book away until tomorrow."

He wasn't ready to stop, but he knew that creating a fuss would bother everyone. So, he did as he was told, waited for her to turn off the light, and then promptly got out of bed, dressed again and then snuck out the back stairs with his book in his hand. He'd done it many times before that summer, and was accomplished at staying out all night, if it suited him. He often wandered the estate in the dark, and knew the grounds better than the gamekeeper or the estate manager. He knew where the badger setts were, where the vixen had her pups last spring- and where to get lost when Father was looking for him.

Tonight, however, he wanted to read, so he took his torch with him. When he got to the lean-to, he opened the padlock- it was really easy to guess the numbers having watched James yesterday put some paraffin back in it.

He'd read four more pages when his torch went out. He shook the batteries in the hope of getting some more power, but it stayed dark. That's when he remembered the box of matches. James was a smoker.

So, when the wick wouldn't light and he dropped the match, he expected it would go out. When it landed on a rag, however, it suddenly burst into flame. _Why did that happen? Cloth doesn't burn as quickly as that; it smoulders first._ Mycroft had given him a chemistry set last Christmas, and he'd learned a lot about what burned and what didn't- always under Mummy's watchful eye. She only let him use the burner when she was there, and he had learned why.

So, this surprised him. He looked around the lean-to in the brighter light- and spotted a cloth. _Like a fire-blanket_- cut off the air and the fire will go out. It was basic chemistry that his mother had taught him when he first got the kit- she put the tube with the fire blanket on the wall, and showed him how to use it.

So, he took the cloth and tried to smother the fire. But, it didn't go out; instead the cloth caught fire and suddenly the place was hot and smoky and very bright, and very scary. He picked up his book and ran out. When he got up to the house he just went back up the stairs, changed back into his pyjamas and went to bed, clutching his book to his chest.

The next morning, the gardener was fired. "You have no excuse, James- leaving oil soaked rags in the shed. What were you thinking? You know that Danish oil impregnated cloth needs to be kept in an airtight container, or it will spontaneously ignite. We've just lost the tractor lawn mower as a result of your carelessness."

On Saturday, Sherlock told his mother the answer to the puzzle. "It's people, isn't it? Humans are omnivores. We eat meat and vegetables and milk."

She reached her hand out and their fingers touched. "Yes, Sherlock. You're a clever boy." He didn't reply, and spent most of the rest of the afternoon trying to figure out how the cloth might have ignited on its own. If he could figure that out, he'd feel happier.


	6. Chapter 6

**Periodic Tales: Oxygen Part Two:**

* * *

**Dioxygen- O(2), the most abundant form of oxygen in the earth's atmosphere**

* * *

"_Any inflammable substance in the form of a gas, a liquid, or a fine dust can explode when mixed with air. If smouldering wood is placed in pure oxygen, it will combine with the oxygen so fast that it will become hot enough to burst into flame again."_ Barbara Lowery had moved on in the book now to the element, oxygen. She'd never studied chemistry at school; she'd done biology. Despite the fact that the book seemed to be aimed at teenagers rather than a developmentally challenged boy, she was finding the book quite interesting. It was not just factual but it explained things that she wasn't sure she'd ever been taught. For example, helium was an inert gas- it didn't join with other elements. She laughed when she read the next bit: "_Some people seem to think there is something aristocratic about this aloofness. For that reason, the group is sometimes called the noble gases."_

Sherlock looked up at the sound of her laughter, curious. He was starting to accept her presence. No eye contact yet. She glanced down at her watch. _Oops- it's nearly six o'clock; got to get going._

"Sherlock, I need to get back to work now. We'll have to pick this up later. Maybe one of the nurses on the next shift will read to you."

The boy just reached his hands up, not looking at her, but off over her shoulder. His face was impassive, but she knew what he wanted. She handed over the book, and he opened it. But, this time, instead of resuming where she left off, he flicked back through the pages to Hydrogen and began to read. "Why are you re-reading that bit, Sherlock?"

There was no reply, or even recognition that she had spoken. She sighed.

According to the junior doctor she handed over to each morning, the ten year old had been making considerable strides in communication skills before his mother's death, but the loss of the person to whom he had emotionally attached had derailed that progress completely. He had not spoken once in the entire four and half months that he'd been at the hospital.

_Is there no other family then?_ Perhaps Dr Molhotra would know. It was a sad part of her role as a night nurse that she rarely ever met the patients' families or got to know their background.

The young doctor frowned. "A father who has never visited and I think an older brother, but I'm not aware that he's been to see the patient- I think he's away at university or something."

"Sherlock seemed very quiet tonight- in fact slept through until five o'clock, which he's not done since I've been here. Is he on a new drug regime?"

"No, nothing new in terms of drugs." He scanned down the chart. "Oh, he had an ECT session yesterday afternoon. That tends to put people to sleep for about ten to twelve hours minimum."

Her face must have betrayed her surprise. "I thought that ECT was no longer used with children."

"Yes, it's never been used much, but it was a bit more common a decade ago than it is now. I have to say it seems a pretty extreme therapy, but all the protocols have been followed. The patient can't make informed consent, but the parent actually asked for it."

One of Barbara's previous jobs had been in a psychiatric ward in York. Some of the adults with schizophrenia or severe depression had been treated with a course of ECT. She'd been surprised at its effects. Pulsing a high voltage electrical current through someone's brain had always seemed to her a rather drastic measure. She'd seen adults wake up from such sessions disorientated, confused and with significant memory loss. She wondered what effect it could be having on the ten year old. Perhaps that was why he was re-reading sections of his book. _Maybe he's trying to remember what the ECT made him forget?_

oOo

"Sherlock, you always say that you delete stuff that isn't important to…keep on your hard drive, but I really can't understand how you could forget that smoke inhalation is dangerous." He'd arrived at the scene about twenty minutes after Sherlock had texted him, but it still wasn't quick enough to stop the consulting detective from chasing the suspect into the burning building. When the Bulgarian car mechanic was overcome by the smoke, Sherlock dragged him out of the back door into the waiting arms of Lestrade's team. The firemen were now dousing the burning garage, which was full of odd barrels of industrial chemicals. They had been evacuated to a safe distance, and the suspect rushed off to hospital in the first ambulance on the scene. It had been Lestrade who called the second ambulance, worrying about Sherlock, but he gladly handed the task of getting the detective to accept medical treatment over to John, as soon as the doctor got there.

His flatmate was now sitting on the back of the second ambulance, not really wanting to be there, but not well enough to stand up and stalk away. The paramedic placed the oxygen mask onto Sherlock's mouth and nose, pulling the straps tight so the oxygen would maintain its pressure and high flow. The pulse oximeter was clipped to his finger, and Sherlock stared at it as if insulted by its presence.

He tried to speak but the mask muffled his words. "I'm fine."

John put his hands on his hips. "Sherlock, you don't know whether you're 'fine'; the effects of carbon monoxide poisoning are not at all clear at the start. We're going to the hospital to get you checked out. At the very least, you could have burned your throat, your bronchi- when they start to swell, you'll go into respiratory distress. Without proper level of oxygen in your blood, you could go into cardiac arrest." He snapped. "Knowing you, you'll be still saying you're fine when the paramedics say you're coding."

He literally shoved Sherlock into the back of the ambulance and the paramedic slammed the door shut before the brunet had a chance to recover his balance. When they got to the hospital, the doctor explained to the Emergency Department team what had happened. Sherlock pulled the mask off and said, "It's unlikely that I've been exposed, John. No sign of my skin turning pink."

"You know as well as I do that skin discoloration is only one symptom and it doesn't always appear. Carbon monoxide poisoning is _serious_."

"I know that. The brain and heart are damaged when carboxyhemoglobin (COHb) levels exceed 20%. That's because the affinity of haemoglobin for CO is over 210 times higher than for O2. CO easily displaces oxygen from haemoglobin and binds to intracellular myoglobin in the myocardium. This negatively affects the oxidative phosphorylation and consequently, the energy source of heart muscle."

The Emergency Department doctor listened to the chemistry lesson and smiled. "Well, there's no sign of hypoxia affecting either his lung capacity or his brain function if he can get through all that on one breath."

But just to be sure, he ordered that Sherlock should be tested for the COHb levels, and given a blood glucose test, a cardiac enzymes test plus an ECG to see that nothing was amiss. And, despite the consulting detective's protests, when the results came back showing evidence of mild exposure to carbon monoxide, he also ordered an overnight stay in the hospital, so Sherlock could be monitored should any headaches, nausea, arrhythmias or chest pain occur, due to myocardial ischemia. And he was to keep the oxygen mask on, too, to accelerate the removal of the CO.

John just told him to shut up and stop whinging. "So do as the doctor says, for once, Sherlock. You know that chemistry doesn't lie. Breathing is definitely _NOT_ boring."


	7. Chapter 7

**Oxygen- Part Three:**

**Ozone- O(3) a reactive allotrope of oxygen that is very destructive and damaging.**

* * *

"Why can't I see him?" Mycroft had just arrived home for the Easter Break, three weeks away from the academic hot-house of Balliol. He'd enjoyed the second term content and its focus on current UK politics; it gave him a chance to focus on something other than the gaping hole left by his grief. His mother had died one week after the new term had started, but he had permission to delay his return to Oxford until after the funeral. He'd caught up easily enough, but the demands of doing so meant he had little time to think about things he'd rather not think about.

His father was standing at the fireplace in his study. He was a tall, imposing figure; his face betrayed absolutely no emotion at all. He turned his dark blue eyes on his elder son and heir, who had inherited the Viscount title on his mother's death. "Because there is no point, Mycroft. No purpose would be served for either of you."

"I don't understand why you won't even tell me where he is."

"Because then some sentimental weakness might lead you to think you should go see him or try to communicate."

_Yes, well- he is my little brother. _Mycroft was trying to hold his temper, but finding it hard in the face of his father's implacable refusal. "Family loyalty is not a weakness, father."

"In his case, it is. There is nothing you can do. He was born defective. He can't be held responsible for that, but there is no need for _you_ to feel obliged in some way. I won't have him hold you back. You have more important things to think about, young man. He's where he can be cared for, by people who are specialists in dealing with people like him. That's all you need to know. This family has done its duty; time to move on."

"Mother would be …distressed by your treatment of Sherlock."

Playing that particular card was a mistake, as Mycroft realised when his father's face contorted in anger and he crossed the space between them. Now looking down into his son's eyes, Richard Holmes said very quietly, "You will not take that tone with me, young man. Caring is not an advantage. It's because of him that she neglected her own health. I should have made her send him away years ago. If I had, she might still be alive."

Mycroft stood his ground. His own anger drove the reply, "Pancreatic cancer is highly lethal, Father. She was unlikely to survive it, with or without Sherlock. You're not being fair."

"Fair?" The older man's sneer was evident. "What's fair about a wife spending all of her time with a retarded child? What's fair about that parasite sucking all the life and energy out of her? Life isn't fair, Mycroft. I would have thought you'd have figured that out by now."

_In for a penny, in for a pound._ He took a deep breath. "I have figured out that the distance between you and mother was not all one sided. Your infidelities helped."

He could feel the barely supressed rage, and watched his father's right fist clench. _Are you going to hit me, the way you do Sherlock? That would be new for you and me, but perhaps it's only fair._

"You have no idea what you are talking about."

Mycroft tilted his head and looked puzzled. "Don't I? Ever since that memorable occasion at the dinner table when Sherlock outed your relationship with…what was her name? Ah yes, Sharon Williams, your marketing director…I know there have been others. Mother knew, too."

The anger burned incandescent in his father's eyes. "Maybe when you are older, have a family of your own, you will realise that it takes two, Mycroft. When one partner in a marriage is totally consumed by a child's needs, the other is often driven to find company and comfort elsewhere."

Richard Holmes turned back to his desk. "Now, that is enough of this conversation. I won't dignify it by wasting any more breath. Oxygen just feeds a fire. So, there will be no further talk about the boy. He's gone. And you need to focus on your studies."

But Mycroft couldn't let go; he just couldn't. When his father made him return to university a week after the funeral, Sherlock had just been sedated by the family doctor. He couldn't say goodbye because his brother was finally asleep after almost a week of continuous crying. The boy hadn't eaten or slept, wouldn't tolerate being touched and had stopped speaking. As much pain as Mycroft felt about his mother's death, leaving his brother in such a state was almost worse. _At least her suffering is over._ He'd called home the day after getting back to Oxford, and been told by the housekeeper that his father was away "indefinitely" on a business trip. Sherlock had been moved to a clinic, where he could be cared for. She didn't know where, because she hadn't been told.

So he faced his father now, and asked the question that had nagged at him the whole of the academic term. "You mean him to stay institutionalised -what, forever?" He sounded incredulous.

"It's not your concern. You are to focus on university, young man. You have a future. He doesn't."

It was as if there had been an electrical discharge; the air tingled. Mycroft couldn't bear to be in the same room with his father any longer. Without a word, he just turned and left. He went upstairs, packed his bag and called down to the chauffeur. "I need a lift to the train station, Michaels. Could we leave right now?" He didn't say goodbye to his father.

oOo

John surveyed the devastation. The flat was normally shambolic, chaotic and untidy, but the living room now looked like a tornado had swept through. Books were thrown off the shelves, piles of papers kicked over, whatever was on the dining table when he left was now the floor, including Sherlock's laptop. It was still on, half open, so John started by picking it up and closing it properly.

He looked over at Sherlock, who was sitting – well, not actually sitting- in the chrome and leather chair by the fireplace. The tall brunet's knees were drawn up to his chest, one of his long arms wrapped around them, and his head buried in the space between his legs and torso. All John could see of his head was the mass of dark hair, looking even more unruly and dishevelled than normal. Sherlock was a picture of misery.

"It's not your fault, Sherlock. He was intent on killing his children, no matter when we got to him. He'd timed it all out. Getting there any sooner would have just made him do it quicker."

The case had been horrible. An estranged husband kidnapped his own children- a son and daughter- because the wife wouldn't allow visitation rights. She'd applied for a court order to keep her husband away, but the police were not always around, and she'd never anticipated such extreme steps by the man she married. That his schizophrenia wasn't diagnosed didn't matter. She was hysterical with fear when a child's ear was delivered in a box through the post. She came with it to Baker Street and begged them to take the case.

Sherlock proved it wasn't from the son or daughter even faster than a DNA test- "Ear shapes, John, are unique. Look at the photos supplied by the wife. The antihelix, helix and concha for both of her children are different from the sample supplied."

"But where would he get an ear- a fresh ear at that?"

"Now you are _finally_ asking the right question!"

After a number of false starts at hospital morgues and funeral homes, Sherlock eventually found the answer- a crematorium- and tracked down which one in a matter of hours. A visit indicated that there'd been a break-in several nights previously, but "nothing was stolen apart from some embalming fluid, so we just assumed it was kids doing a bit of thieving to pump up their marijuana smoking."

That had seemed a dead-end (no pun intended), until Sherlock deduced a link between the crematorium and the husband, whose mother had been cremated there four years before. John and he eventually found the care home where the woman had died- now closed. They arrived at the abandoned building, and searched it with a police team. After twenty minutes, they found them in the attic. The two children's bodies were still warm; their father unconscious, but he died before the ambulance arrived. The note attached to the man's coat was blunt. "They are my children and I won't let you have them."

"I should have _known_, John. We wasted time looking at morgues and funeral homes, when it was obvious that the man would want to cover his tracks. He simply removed an ear from a body due to be cremated the next morning. Pull the girl's hair down over where the ear had been, and there'd be no reason for the crematorium attendant to stop. The body is burned, and combustion removes all evidence."

When they returned to the flat, Sherlock disappeared into his bedroom and didn't emerge until the following morning. He was terse and tense, but when John was called by the clinic and asked to come in for a few hours to cover for an illness, the brunet waved him off. "Go, at least one of us should be useful today."

When he got back, it was to the ruins of Sherlock's rage about his failure.

"Sherlock?" John's voice was gentle, but insistent. "Please, look at me." He was worried about the total lack of response. Was this the aftermath of a meltdown? _Yeah, what else? And I was stupid enough to leave him alone._ He glanced into the kitchen and saw the devastation of broken glass. Sherlock's experimental kit lay in shards and splinters. The microscope was on its side under the table. That's when the doctor's nose detected a scent that was an occupational hazard for a medical professional- the metallic tang of freshly oxygenated blood.

"Sherlock, what have you done to yourself?" This was more insistent, not as gentle. Looking at the brunet in the chair, John realised that he'd tucked his right hand in-between his knees and his body. "Have you hurt your hand? Let me see."

There was no response. He knew Sherlock loathed being touched, but needs must. He put a hand on the man's shoulder, and when there was no flinch or reaction, he then reached in to try and pull Sherlock's right hand free. He couldn't see it, but knew by the wet touch that he'd found the source of the scent; the hand he grasped was slick with blood. It's a unique texture- warm, wet, and yet with a viscosity distinctively different from plain water.

He pulled the hand out and grimaced at the sight. Sherlock's palm had a jagged gash, about the size of a fifty pence piece, right in the middle. It was very deep and it was bleeding heavily. The front of his pyjamas, now visible to John for the first time since he arrived, showed that the bleeding had gone on for some time.

Sherlock was strangely passive. He let John check for tendon damage, clean and suture the wound, and sat absolutely still through the whole procedure, unmoved and unmoving. He had not lifted his head to make eye contact once since John had arrived. But he didn't stop John from seeing to the injury, and when it was done and bandaged, John got him a glass of water.

"You are lucky that I came home when I did, otherwise you would probably need a transfusion. Drink it, Sherlock. You need to replace the fluids."

Awkward with his left hand, Sherlock complied obediently, and then held the empty glass in front of him, eying it with a strange expression on his face. His grip started to tighten around the glass, as if testing to see when it would break under the pressure. John quickly snatched it from his hand.

"You want to break glass. Why?"

He didn't really expect an answer, so was surprised when he got one. "It puts the fire out."

The doctor's head tilted as he scrutinised his friend. The tone of voice was utterly flat and quiet. There was no evidence of a fire in the flat, nor that there had been one. No charred scent, no smoke alarm, no fire extinguisher residue. "What fire?"

Sherlock blinked. "When I get so angry that I can't control it, then smashing glass works. The noise, the…sensation, the pain- it removes the oxygen feeding the fire in my brain. It just …goes out."

"It also results in blood and destruction, Sherlock. Can't you see that?"

Sherlock glared at him. "Save the sanctimonious preaching, John. Surely you were awake in med school when they covered NSSI. Non-Suicidal Self Injury- it's not rocket science; it's amygdala activation and stimulation of the limbic circuitry. Think of what I do as a form of self-medication. I am using the glass breaking as a form of conditioned neural stimulation. Believe me, the consequences are far less damaging than letting the fire rage unchecked."

John rolled his eyes at his friend's explanation. In one sense, he was glad for the sarcasm and cutting edge to Sherlock's explanation. Sarky he could deal with; silence was more worrying. Looking up at the ceiling, the little red light on the smoke alarm up there caught his attention.

"Sherlock, next time you feel that self-combustion is a possibility, give me a warning of some kind. I'll hang around and make sure that you don't have to resort to such drastic measures."


	8. Chapter 8

**Lithium Li 3 6.941**

_An alkali metal, which under standard conditions is the lightest metal and least dense solid element; it floats on water. Highly reactive and flammable, lithium never occurs freely in nature, only appearing in compounds. Trace elements of lithium are present in all organisms, yet serve no apparent vital biological function. _

* * *

**Part One: Power **_An important element of heat-resistant glass and ceramics, lithium has many other uses in manufacturing, too._

* * *

"There's been a coup in Bolivia." It was said with breathless excitement.

Startled, John looked up from his bowl of cereal. In his experience, that tone was reserved for bizarrely complicated and usually gruesome murders. He and Sherlock were sitting at the table, both in their pyjamas and dressing gowns. As usual, Sherlock was devouring papers, while John was more intent on re-fuelling with food.

"So? Isn't that Mycroft's area, not yours?

"Oh, John, _this_ one is important."

"I thought coups in Latin America were sort of…expected."

Sherlock had grabbed the second section of the Financial Times and was quickly flicking through the pages of stock prices. "Ah ha!" With glee, he turned to John and pointed to the commodity prices that were in tiny printed numerals.

"John, this is REALLY important."

"Why?"

"Lithium!"

John tried to keep the perplexed look off his face. "Okaaay, I'll bite. What's a drug got to do with a coup?"

Sherlock rolled his eyes. "You are an idiot, John."

"Maybe, but I will remain one if you don't bother to explain."

"Lithium is an alkali metal; 60% of the world's production comes from Latin America, and most of that is from Bolivia and Chile. It's mined from the salt flats there; cheap, easy and accessible in a way that China's and Australia's deposits are not, because lithium there is in ore form and has to be dug out and processed, much more expensive and time consuming, as well as environmentally damaging."

_How does he do that all on one breath? He must have amazing lung capacity. _John put his cereal bowl down. "That's supposed to explain your 'Ah hah moment', is it?"

Sherlock looked confused. "Yes, of course."

"Well, it doesn't, so a little translation or subtext is needed, Sherlock."

His flatmate rolled his eyes. "_Batteries_, John. Your laptop and phone depend on lithium batteries. Lithium has the highest electrical output per unit weight of any battery material. It's rechargeable. Demand for lithium batteries going up by over ten per cent every year, but the known sources of lithium are not increasing. And now every car manufacturer in the world is working on electric cars that will use lithium batteries. What do you think that is going to do to the price of lithium? I wouldn't be surprised to find that the people behind the coup are in some way connected to big business- either that, or the Chinese government is making sure to secure a good supply for the future." He smirked. "Chemistry is behind most of the important events in world politics, John."

"Tell that to Mycroft, will you?"

"He already knows, John; why do you think he keeps trying to recruit me?"

oOo

"What do you have to say for yourself, Sherlock? Why did you vandalise the tape recorder?" Richard Holmes was a tall man used to getting his own way, and to the twelve year old standing in the study with his eyes glued to the floor, the tone in his father's voice carried menace. Sherlock was trying hard to stand still, but his hands clasped together behind his back were shaking. _Fight or flight; that's what the doctor at the clinic called it. I've got to control this, or he will get even more angry._

On the desk behind his father lay the pieces of his father's memo recorder.

"Speak up! Don't play dumb, boy; you will tell me why."

Stuttering wasn't acceptable either, so he tried to put the sentence together in phrases, and say them quickly enough before his nerves tangled his tongue up. "I got curious, sir...about the power. Wanted to know how the electricity stored in the batteries powers the recorder. The batteries are re…re-chargeable. Never seen that before, so I w…wa…wanted to understand."

"So, by _playing_ with it, you destroyed it without thinking about what was recorded on it."

Sherlock looked startled. "Was there something recorded on it?"

"Yes, you mindless cretin, a lot of work was lost when you took it apart. Hard work of mine that took hours. Recorded instructions to the people who work for me. Work that I now have to do over again, thanks to your stupidity and carelessness."

The boy kept his eyes on the floor. "I'm sorry. I didn't know that there was something important on it." _Even if you think you are right and he is wrong, always apologise, Sherlock, if you want to avoid making him even more angry. _ He kept repeating in his mind 'Mycroft's Five Steps to Avoid Making Father Angry'. He'd done Step One already by admitting he was responsible; the apology was Step Two.

"I've told you before not to play with anything in this room, Sherlock."

"I didn't _play_ with it…I investigated it." He watched as his father's eyes narrowed at the contradiction, his anger becoming a heat that the boy could almost feel. Sherlock's hand trembled; he'd just broken Step Three- don't argue.

"The recorder was a high specification business machine, worth a lot of money."

That comment irked Sherlock. "You own the company, and there must be lots more recorders like this in the office. It can't be irreplaceable."

Because his eyes were down on the floor, he didn't see it coming. The slap was sudden and nearly knocked him off his feet. He gasped, but didn't cry. He bit his lip and just kept repeating in his head, hearing this brother's voice. _Remember Step Four- don't be sarcastic. _

"What punishment do you think is appropriate, Sherlock?"

"I don't know, sir. It's for you to decide."

His father was silent for a moment and then, "Your chemistry set will be given away. Some charity might find it useful for a boy who has shown scientific skill and has more aptitude than you. It's only fair to give it to someone who can actually benefit from it."

Sherlock blanched. He had few possessions that he really valued, and his father knew just how important the chemistry set was to him. "But, Father…." He couldn't disguise the pain in his voice. "I can work, do chores, earn money to pay you back for the recorder."

His father had already turned back to the desk and he swept the pieces into the rubbish bin. "That's enough. If you can't be trusted to respect other people's property, then you can't have any of your own. Get out now- and don't let me catch you in here ever again."

Sherlock left the room, trying but failing miserably to deal with Mycroft's advice. _Step Five- accept your punishment and learn from it._ All he had learned is another reason why he hated his father.


	9. Chapter 9

**Author's note: **The first part of this is for SailOnSilverGirl, for obvious reasons and in thanks for her support.

* * *

**Lithium **

**Part Two: Nuclear **

_Lithium deuteride was the fusion fuel responsible for the run-away yield reactions in the first hydrogen bomb test in 1954, which led to the most significant accidental radiation contamination ever caused by the USA. _

* * *

Mycroft was chewing the end of his pen as he considered this week's essay assignment-

"_The needs of the many outweigh the needs of the few, or the one."_ _Discuss the difference in how Jeremy Bentham and John Mills would react to such a statement if it had been made to them._

It was a puzzle. Normally, his political philosophy tutor set a question using a quotation that was well known. Last week's question involved a quote from Aristotle, asking if St Thomas Aquinas was an Aristotelian Christian or a Christian Aristotelian. That had been easy, and he'd recognised the quote as coming from Plato's second Book of Dialogues. But none of his research so far had been able to identify where the mystery phrase about the needs of the many came from, and he was running out of time. It was due in the morning. He really _hated_ doing things so last minute. The easy bits were done- comparing Bentham and Mills's views on utilitarianism was a simple task, but he wanted to show off his erudition by linking it to the quote.

The watery spring sunlight came in through the gothic windows of the college library's mezzanine floor. His rooms up staircase four in the back quad were cold; he preferred the warmth and quiet hum of activity in the library. One of the other first year PPE students, Jonathan Pember, was sitting across from him, trying to grapple with the same essay.

"What's bugging you, Holmes? You're such a swot that you've usually finished your essay by now and are prepping to wipe the floor with us when we meet Hodges tomorrow."

A little defensively, Mycroft looked up at the blond sitting across from him- a rugby boy, big and a bit thick, if truth be told, but well liked amongst the PPE cohort. "Bentham and Mills are not an issue for me, Pember."

The chap laughed. "Yeah, but who would have thought that Hodges was a Star Trek fan? I mean, really- he's such a dinosaur. Probably watched the first television series back in the sixties. Must have been keen if he then went off to the Wrath of Khan film, don't you think?"

Mycroft kept a tight lid on his shock. The quote wasn't from one of the great philosophers, but from a wretched television programme? It beggared belief. He'd never watched television at home, and access at prep school and then Eton was pretty limited. He had absolutely ignored this science fiction thing from America.

The rugby player leaned over a little conspiratorially. "Can't say I'm much of a fan, so I chatted up Brookes. Being a science nerd, he's a real trekkie. Got me the character who said it and everything. Now, just need to crack the books about 18th century philosophers, and I'll get going."

Mycroft excused himself and headed off to the Porter's Lodge, to find out where Brookes' rooms were; he needed some more information. Thirty minutes later he was skim-reading the novel that was based on the film, written by Vonda K McIntyre. The second in command of the vessel was an alien by the name of Spock. _Wasn't he a child psychologist?_ Mycroft vaguely recalled his mother reading a book by some doctor with that name, when she was trying to figure out what to do with Sherlock.

This strange character had sacrificed his own life to save the ship, enduring a painful death from radiation burns. The quote was one of his dying words, a reference to his home planet's philosophy. But, why would the professor simply include such an obviously clear reference to an extreme utilitarian ethic? What was the value in that? Why not just use a classical reference? Puzzled, he kept reading.

When he finished the novel, he pondered the thinly disguised moral teaching which underlay the work.

"What did you think of it?" Brookes was curious. Holmes was just _so_ not the type to read scifi that he was startled by his request. He was a little in awe of the guy, whose reputation as a brilliant scholar made the other students respect him, but he seemed to have few if any close friends.

Holmes pushed his straight chestnut red hair out of his eyes and looked at Brookes with a perplexed frown. "I don't get it. What's the significance of the phrase-the needs of the many outweigh the needs of the few or the one?"

"Well, that only becomes clear in the next film, _The Search for Spock_. You see he gets…well, sort of resurrected. And the captain and the other officers sacrifice the ship and their careers when they realise that the needs of the few, or in this case the one –Spock- do matter more, because without Spock the planet Earth wouldn't have been saved in the next film."

_Oh. Now that makes more sense. _"So, it's all about when a utilitarian morality is undermined by the Kantian categorical imperative."

"If you say so, Holmes, but I haven't a clue what you're talking about."

Mycroft completely re-wrote his essay that night. When he finished at two o'clock in the morning, he pondered the meaning of it all. Some things are more important than the "happiness of the majority." Somehow writing it made him think about Sherlock, and he felt guilty. Thinking through these issues from a philosophical point of view made him realise his own failings. He'd let the fire go out; the anger he'd felt at his father's betrayal of his brother had dimmed when Mycroft got back to the routine of Oxford and academic life. Well, he didn't intend getting radiation burns from such a toxic philosophy. He reached for the file he'd started when he'd first returned after learning that his brother was gone. It was time to start looking again in earnest for that clinic. His father might think it "better for everyone" if Sherlock was hidden out of sight, but he was damned if he was going to let him get away with it. _The Search for Sherlock_ was his next mission.

oOo

When nuclear physicists go missing, it should be a matter of public interest, but the disappearance of Dr Salim Kharoti had not been mentioned yet in the papers.

"Take the case, Sherlock." Mycroft was tapping the base of his umbrella against the wooden floor by the fireplace.

"Why should I?"

"Because it is challenging, and important."

The brunet smirked. "You mean your people have proved useless at it. That doesn't mean it would be challenging for me. And you know very well that your definition of 'important' and mine are very far apart."

Mycroft sighed, "Do you _really_ need me to feed your ego every time I ask you to take a case?"

"Is that a rhetorical question, or an admission of defeat?" Sherlock smirked, but kept his eyes focused on the slide in the viewfinder of his microscope. He'd put the cover slip on the specimen and slipped it under the clips while his brother was pondering how to entice him.

The British Government scowled at his brother's cool demeanour. "Why do you have to be so difficult?"

"Why do you have to be so obtuse?" came the almost immediate reply.

"Doctor Kharoti quit his job and then promptly went missing ten days ago, after erratic behaviour. We have been unable to determine his whereabouts. A nuclear physicist working at the Atomic Weapons Establishment, he is on a watch list not just because of his job but also due to relatives in Pakistan being a little less than upstanding citizens. His house has been searched, but nothing came to light. On the one hand, he could have joined a terrorist cell and is helping them prepare a dirty bomb."

Sherlock interrupted. "That's what the CIA thinks, and MI6 are willing to go along for the ride so as not to antagonise the American cousins."

Mycroft frowned. "That much is obvious, brother." He inspected the point of his umbrella. Tapping it against the floor might make his impatience with his brother clear, but the poor state of the Victorian floorboards might not be helping the umbrella, so he decided to stop.

"On the other hand, he could have buggered off with his latest girlfriend?" Sherlock said helpfully. He still hadn't raised his eyes from the microscope.

"Perhaps. Or he's been kidnapped by criminals and we are about to receive a ransom note."

Sherlock smirked again as he looked at his brother. "No, that's what MI5 thinks. What do _you_ think, brother, and why is no one listening to you?"

Mycroft gave up. His brother had always been able to read him, as if he were an open book. No one else could. _Thank God._ "Very well, I do think his disappearance is the result of something more personal, but I can't seem to get anyone interested in that angle; they all have so many agendas running that it rather gets in the way of the facts, I am afraid. That's where you come in. You have no _special interests_ to preserve, and will find the truth rather more easily than anyone else. So, I think of it as an exercise in resource management."

Sherlock looked offended. "So, I am _cheap and cheerful, _am I?"

"Oh, I wouldn't overdo the cheerful bit, would you?"

Sherlock blew him a raspberry and returned to his microscope, unclipping one slide and inserting the next onto the stage. He had twenty more to go in this statistical cohort, looking at the growth of streptococcal bacteria on the surface of dead human skin tissue. It was a tedious process of killing the bacteria, staining and mounting the slides, which had taken him half the morning. It was an interesting case of a funeral director who had regularly suffered impetigo suddenly succumbing to an invasive infection of necrotising faciitis, a form of gangrene. The medical examiner ruled it natural causes, but Sherlock was investigating a different hypothesis – that someone had doused the cadavers he was working on with the bacteria, in order to provoke the more serious infection.

"It will take you an afternoon, if that. The man lived in Padworth, only a couple of miles from Aldermaston. You can take one of my drivers; investigate his house, do what you do so well- snoop."

Sherlock glowered at his brother. "You're not selling this very well, Mycroft. If you continue to insult me, you can just show yourself out the door."

Mycroft's face betrayed the tiniest of smiles. He was also adept at reading his brother's moods. The fact that he had not been told to leave five minutes ago meant that Sherlock was willing to be …incentivised.

"Would a microscope with phase contrast optics be useful in your work?"

That got Sherlock's attention. "Oooh- _live _specimens. You must _really_ want to score points with Five, Six and anyone else who doesn't believe you." He looked up at the kitchen wall and thought. It didn't take long.

"Yes. Have your driver here tomorrow morning at 8, with the file."

In the end, it didn't even take the morning. Within fifteen minutes of getting into Doctor Khorati's house, Sherlock had deduced that the man was in Birmingham, undergoing treatment for skin cancer, which he believed to have been caused by chronic low dosage lithium radiation exposure at work. He wanted to keep it quiet so he could assemble a case for litigation on health and safety grounds. Sherlock delivered the details to his brother by text. He also provided a url link to the specifications for the top end Olympus CX31 Halogen Phase Contrast microscope. Everyone has their price.


	10. Chapter 10

**Author's Note: ** The first part is for Kate221b and the second for SailOnSilverGirl, who asked how Mycroft and Sherlock reunite. Thanks for all your reviews and help, ladies.

* * *

**Part Three: Drugs**

**Li12CO3 and ****Li3C6H5O7 **

_Lithium carbonate and Lithium citrate are mood stabilising drugs used in the treatment of bi-polar disorder, due to the neurological effects of the ion in the human body. Ihey can be used as well in the treatment of unipolar depression and severe depressive episodes._

* * *

"John, head into the bathroom or look in a bedside cabinet, if there is one."

"What am I looking for when I get there, Sherlock?" John closed his eyes in frustration. Sometimes he wondered if the consulting detective thought he was a telepath. The number of times he just _assumed_ that the doctor knew what he wanted was increasing.

"Medicine, of course. What else? Why would I send _you_ otherwise?"

John sighed, "Sherlock, the average household has dozens of over-the-counter medicines and lots of prescription drugs, as well- so, anything in particular?" He'd been sent on this expedition from Barts' mortuary, when an unidentified teenager turned up dead, with no obvious signs of injury. Molly had been puzzling over the cause of death for hours. On the one hand it was obvious- renal failure- and the body was severely dehydrated. But what had caused the kidneys to pack up was not clear. The boy didn't have a mark on him, the stomach contents proved to be predictable- pizza, cola and popcorn, which tallied with the ticket stubs found in the back pocket of the jeans he'd been wearing. He'd collapsed in the lobby of the cinema, had a seizure and died before the ambulance could get there. She'd sent tissue and blood samples off to be tested at the pathology labs, but they were a bit backed up and could only promise the results "sometime Thursday afternoon."

She'd sighed, "He seems so young. He's a mystery wrapped up in an enigma. No idea who he is or why he died. No match on fingerprints, but I suppose that's not surprising, given his youth."

Sherlock and John were already in the morgue examining a cadaver that had been in the Thames for four days when Molly asked them if they could figure out a way to identify the boy. "I just hate unknowns; it seems so unfair on his family and friends." There had been no wallet or phone, no ID of any kind, just a single unlabelled key in a pocket.

It took the consulting detective only twenty minutes to deduce the name of the young man, based on his clothing and boots; an unusual badge on his jacket lapel turned out to be from a small hiking club, a trail that led to a name: Richard Atkinson, aged 18. He lived at home; the club was able to provide an address and telephone number from the insurance release form signed by all members. An attempt to contact his parents by phone went unanswered, so John went to the house to meet the local police there. If there was a parent on site, then the constable would pass on the bad news. If the house was unoccupied, the police presence would allow him to use the key to investigate the scene.

Sherlock decided to remain behind and carry on working on his drowned cadaver, but he promised to contact the boy's Sixth Form college, to see if the teachers could provide any information about the possible cause of death.

John went through the medicine cabinet- a number of different anti-depressants, but all in the name of Robert Atkinson, presumably Richard's father- a fact backed up when the constable read the name on unopened post sitting on the hall table. The master bedroom looked tidy, if a bit dusty. The teenager's room, on the other hand, was a total shambles. The kitchen was even worse, with dirty dishes piled high in the sink, and the fridge was virtually empty. John's mobile went off when he was checking the kitchen cupboards. He checked the caller ID and picked up.

"Sherlock, the boy's father was on some medication for depression- the usual cocktail, but the prescriptions are all at least five months old. Everything else is what you'd expect- aspirin, antacids, the obvious stuff."

"Yes, well, that date would be right, because Robert Atkinson died four and a half months ago. According to his college supervisor, the father killed himself by driving his car at high speed into a wall. Verdict was suicide, brought on by clinical depression. He was bi-polar and had been struggling for years. The supervisor said the son took it very badly. He couldn't focus, was referred to the school doctor, who sent him off for some tests so he could get extenuating circumstances on submitting assignments- the doctor there thought the boy might also be bi-polar. He's been living on his own in the house. No relatives; mother died when he was six. Can you check the bin? Any sign of a large bottle of lithium?"

John tried to remember if there had been a bin in the upstairs bathroom. He glanced into the one under the sink, and spotted a white bottle. "Hang on." He put the phone down and cleaned off the curry from the label. "Yes- Lithium carbonate. The bottle is big enough to have had dozens of tablets- but it's empty now."

"Look for a mortar and pestle, and a glass."

John looked around the kitchen work surface. Sure enough there was a glass, and the grinder bowl has traces of white powder in the bottom.

"Got it in one, Sherlock. You think this is a suicide, then?"

"Yes- purposive overdose; the tox report will confirm it on Thursday. The serum lithium concentration will be probably between seven and ten molarity* per litre. It's slow acting- giving him plenty of time to enjoy the film, but the dose was enough to induce a seizure, coma and death, even in someone who wasn't taking it regularly. Take a look around his bedroom, see if there is anything from a doctor about an appointment."

John found the torn shreds of a letter in the bin upstairs. He put the bits together again like a jigsaw puzzle and called Sherlock back. "You're right- he tore the letter up, but one of the scraps is calling him in for a psychiatric consultation."

"Case solved; tell the constable that this was a suicide. I will finish up here and meet you back at the flat."

Later that evening, John found he couldn't shake off his feeling that the death had been so sad. Sherlock had been quiet all evening. They'd both given up on crap telly; just not in the mood.

Uncharacteristically, as he was on his way out of the living room toward his bedroom, Sherlock gave a sigh.

"Talk to me, Sherlock."

"The boy must have known he was about to be diagnosed as bipolar, and just couldn't face it, given what his father had been through. He knew the nature of the illness, and decided to take his own life." There as a pause. "Ironic that he chose lithium; one of its supposed benefits is that it reduces the likelihood of suicide."

As he watched the brunet go down the hall to his bedroom, John wondered how Sherlock would know that fact.

oOo

"Thank you for agreeing to see me, Doctor Cohen, on such short notice. I understand that I am lucky to have caught you before your move to South London." Mycroft shook hands with a petite doctor, as she came around her desk to shake his hand and offer him a seat. Her short dark hair framed a pair of lively eyes. She seemed too young to be the same person that he had been told was one of the foremost paediatric psychiatrists in Oxford.

"Yes, well, my apologies for the mess- I am packing up, as you can see." The office was strewn with cardboard boxes half full of books and files. "I take up my appointment at Bethlem Royal Hospital in a week's time. Can I offer you some tea or coffee, Lord Mycroft?"

The use of the title made him blush. He wasn't used to it, didn't think he ever would be, in fact. He could feel the slight tinge of pink on his cheeks rise, but he got it back under control. He'd turned 18 only two weeks ago, and inherited the estates and property that made him financially independent from his father. But in his mind, inheriting the title of Viscount from his mother would always be associated with Mummy's death. "Doctor Cohen, I don't use the title. It's just Mycroft Holmes."

She nodded. "Fine, whatever you prefer. Doctor Saunders at the Radcliffe passes on his compliments, by the way. I gather it was his suggestion that had brought you here."

"Yes. He's an old family friend of my mother. I don't know if he explained my…mission."

The doctor smiled at his use of the unusual word. She was regularly approached by undergraduates at Oxford who were interested in child psychology and wanted her expert opinion, but Saunders said this Holmes needed her advice on a personal matter.

"All he said was that your need for background information was not academic."

"No, it's about my brother. He's ten. My mother died in January this year, and my father has sent my brother to a clinic. He won't tell me where, and he won't discuss his treatment with me. So, it's a little delicate. I need to know that our conversation will remain confidential."

Esther Cohen looked at the young man sitting on the other side of the desk. Obviously public school educated, and very well-spoken; he had a quiet confidence about him that was well beyond his age. Unlike most of the scruffy undergrad students, he was immaculately dressed, and carried himself with a maturity that rather impressed her.

"All conversations about patients are confidential, Mr Holmes."

"Mycroft, please. But, he's _not_ your patient, Doctor Cohen. And if my father were to find out about our discussion, it could be...awkward for you."

That made her smile. "And you, too, I presume?"

"Yes."

He said nothing more, leaving her to draw her own conclusions. _Interesting. He is smart enough to know when to keep silent and leave the choice to me_.

"Right, on the basis of deniability, then this conversation never happened."

He nodded, and then waited for her to speak.

"Then let's begin by you telling me why your brother was sent to a clinic, and what you know about his symptoms."

In the next twenty minutes, Esther Cohen was introduced to the complex puzzle that was Sherlock Holmes. The diagnosis of early development disorders, the communication issues, the repetitive behaviour, self-stimulation, anxiety, the lack of emotion, eye contact and the frequent meltdowns that had featured all through his brother's life. And the time he sat next to a crying nine year old brother on Christmas Eve who asked if a person could die simply if they wanted to badly enough, because he did. "He knew without being told that our mother was dying, and he could see what was going to happen to him when she did."

"Early on a number of specialists diagnosed autism, but none seem able to agree on exactly what form because he doesn't follow the usual patterns, apparently. If you could overlook the autism, he's a genius, a sort of observational savant. What I can tell you is that the only person with whom he had a close relationship was my mother, and, as I said, she died five months ago. He would talk to me, but that stopped at Christmas. Five days after she died on the 20th of January, Sherlock starting crying and couldn't stop. It …"

Mycroft stopped here. His grasp of the medical terminology, description of the symptoms and quietly dispassionate explanation raised him yet again in her estimation. But, in that moment's hesitation, she caught the first glimpse of a young man trying to keep his own emotions under control. She gave him a gentle smile of encouragement.

He looked down, took a deep breath, and continued. "Sherlock's crying _enraged_ my father. He is a scientist, a man for whom logic and facts matter and emotion is…absurd. He has never _connected_ with Sherlock in what one might call a paternal relationship. With the house full of friends and family of my mother, I think Sherlock's uncontrolled, excessive emotional distress…embarrassed him in some way. So, I think he decided to do something about it."

She raised an eyebrow, "Such as?"

"My father owns pharmacology companies. I think he drugged Sherlock. His company has the license in the UK for Priadel, that's lithium citrate syrup, and he has access to sedatives, too. So, the day of the funeral I came back to find Sherlock asleep- and he was kept that way until my father made me return to university four days later. The day after I got back, he sent Sherlock away to a clinic. And he won't tell me where. All I know is that he isn't the NHS system anywhere in the southeast."

She was surprised. "How can you be sure?"

"I've contacted every Child and Adolescent Mental Health Service unit in the southern half of the country over the past four months. None have him on record. I don't think my father would go north- he's had a lifelong prejudice against northerners. So, unless my father falsified his name, he isn't in an NHS facility."

Cohen tilted her head speculatively. "No CAMHS unit would give information out about whether someone was a patient just on the basis of a phone call- even from a family member such as a brother."

He gave her a look, one that said _I'm not that stupid._ "But they would do so to a GP who was asked to forward a patient's medical records. A GP who just happens to have lost the letter requesting the files because the surgery had been water damaged in a flood, and so is calling around to see if it was their unit that had made the request."

She laughed. "Oh, that's good. It would work, too." Her estimation of Mycroft Holmes rose yet again.

"Anyway, after talking to some of my medical contacts about a hypothetical case, I've decided that it's unlikely that my father would put him into the NHS system, because clinical decisions to keep someone as an in-patient couldn't be controlled in the same way. A private clinic is more discrete and someone can be institutionalised indefinitely there more easily. That's my problem. I don't know where to start to find these clinics, and I'm not entirely sure whether the same approach of calling as a GP would work with them. So, that's why I'm asking you. If you wanted to bury a ten year old boy with the symptoms I have described, where would you start?"

She thought about it. She could assume that money is no object with the Holmes family. "Are you sure that it would be in the UK? What about overseas?"

She saw the young man's shoulders drop a bit. "I hope not. It will be hard enough to track him down in the UK."

She realised she didn't want to disappoint him. "Well, let's take this one country at a time, starting with the UK. My next question is whether your father wants to find some therapy and treatment programme that will deal with the severe depressive episode and re-start your brother's socialisation, or…" She stopped here.

"… if he just wants to lock him away forever. Is that what you were going to say?"

"Mmm, yes, not to put too fine a point on it. The list of places will be different, depending on the answer."

She watched Mycroft take a while to consider her question. "I've been asking myself that same question and, to be honest, I don't know the answer. To be sure, I will need a list of both. I don't think he'd put him someplace squalid and horrible. The risk of exposure would be too great if there was a scandal and the place got exposed in some investigation. My father cares too much about the family name to take that kind of risk. So, it could be a clinic that is very expensive but just willing to…go through the motions of keeping a patient quiet and under control indefinitely."

Then he sighed. "But, my father is Richard Holmes. He owns pharmaceutical companies all over the world. Sometimes I think the scientist in him would not be content with so Victorian an attitude – just hide the mentally ill person away. I would have thought, no, hoped that...in his better moments, he would want Sherlock to be helped." Here he gave an almost wistful smile. "I respect my father. He's never done anything to me that would undermine the love I have for him- until this."

She could see his pain, his confusion. Not wanting to think the worst of his father, yet having to deal with what he thought was wrongful behaviour.

"OK, before I go any further, I have to know something. Is it possible that your father is right? That your brother might well be in the best possible place now, being cared for by people who are trained to do the best they can for him?" She looked at him to see what affect her words were having. "I guess what I am asking is, what will you do when you find him, Mycroft?"

She watched the young man drop his eyes, swallow hard and take a breath. Then his chin came up and he said calmly, "Sherlock is my brother. I have loved him since the day he was brought home from the hospital and I saw my mother look at him. She and I did what we could to help him grow up, and before she died, she asked me to look after him. He's all I have left of her now, and I'm all he has left, too. I won't abandon him, simply because my father thinks he's inconvenient."

He continued and she heard the conviction in his tone. "When I find him, I will make sure that he is getting the best possible treatment and that he is helped to live as normal a life as he wants and is capable of having. Above all else, I want him to know that he has not been abandoned or rejected, that he is loved. I am not sure that he fully understands what love means, but that doesn't mean that I don't. He is my brother and I will always care about him."

Esther Cohen made up her mind then and there. "I will help you, Mycroft. Give me a couple of days. I'll write up those two lists for you. Like you, I'm going to hope that your father wants doctors who will treat your brother's severe depressive episode. That will help narrow the likely places. Come back on Tuesday and we'll talk about the best way to get them to tell you if he is there or not."

_* Author's note: __in Europe, mmol_**/**_L_ means millimole per liter, the SI unit in medicine for measuring concentrations, which in America are measured in milligrams per decalitre.


	11. Chapter 11

**Author's Note: **Keeping to the elemental character of these stories, I can't always promise to be in chronological order, so sometimes I will go back a bit in time. This is one of those occasions. Just think of it as a flashback...

* * *

**Carbon**

**C 6 12.017 **

_Non-metallic and tetravalent, meaning there are four electrons able to bond. Carbon is one of the few elements known since antiquity; its name is derived from the Latin carbo meaning coal. The fourth most abundant element in the universe by mass, it is present in all known life forms and in the human body the second most abundant element (about 18.5%) after oxygen. It is known to form almost ten million different compounds, the largest of any element, and is the basis of organic chemistry._

* * *

**Part One - Carbon's First Allotrope ****Graphite (and Graphene)**

_Graphite, from the Greek "to write", is the soft allotrope of carbon. Pencils contain graphite mixed with clay to make it harder; pencil marks are bits of graphite that break off and adhere to the paper when pressed._

* * *

Doctor Molhotra's examination of Sherlock was methodical and quick, but he wasn't getting much co-operation. Still, it was better than it used to be, when the ten year old would panic at the sight of him, and he needed the help of two male nurses to restrain him while the examination took place. Now the boy just sat there in his hospital bed with a sullen look on his face. The doctor had some sympathy; he must have known by now that the examination was always done just before an ECT session. Before using the stethoscope on the child's thin chest, the Asian doctor put down his pad and pencil on the bed. He would transfer the statistics to the chart kept at the nurses' station later: pulse, respiration, blood pressure. He'd also draw a blood sample, to make sure that the current lithium blood serum level was right. It was proving hard to get the dose right, not only because the patient was a child, but also because his weight kept fluctuating. They'd had lots of problems over the months with that- sometimes he would eat, and then stop, requiring a gastric tube. Getting the exact dosage right in such circumstances was always tricky, especially now that they were trying to wean him off of it.

Just as he jotted down the latest pulse reading, his pager went off. A quick glance down at the device and he dropped the pad and bolted from the room- a code up on the next floor, one of the teenage patients.

Impassive, Sherlock watched the doctor leave the ward. As soon as the door clicked shut, he picked up the pad and the pencil. He left the top sheet as it was, but pulled a dozen perforated pages out from the back of the pad. If he was lucky, it would be ages before they were missed. Folding them in half, he tucked all but one of the sheets into his book. Left with one clean sheet, he began to draw a grid, seven boxes down and eighteen across. He used the edge of his book to be sure that the lines of his grid were straight. Sherlock looked at the page that the doctor had completed and saw the date, then transferred that date to his sheet and began to fill in the boxes of the grid with the letters he could remember: H, He, Li, Be, B, C, N, O, F, and so on. There were a few gaps, but he reached number 56, and then drew a line from it to a space below his grid, then another table, this time with only two rows and fourteen columns. The second row of this table he linked back to AC, number 89 Actinium.

Sherlock had trouble keeping track of the days, because they all seemed to be so similar here. Now that he had a pencil, he could keep a calendar in his book, so he wrote the date on the blank page at the back. Reading the book last night, he'd memorised the 103 elements*, and he was determined to keep track of what he was forgetting each time they took him away for treatment. The periodic table would be his test.

When Molhotra returned over an hour later, Sherlock heard his footsteps coming down the hall. After all these months, he knew the difference between his stride and that of a nurse. In a flash, he hid the pencil beneath the hospital bed mattress, and slipped the graph in the back of the book, which he shoved back on the bedside cabinet.

When the doctor entered, Sherlock was still sitting there, looking as if he had not moved at all in the interval. _Still, it's better than when he was first here; then he was virtually catatonic_. The doctor took the blood sample, and then picked up the pad. Now where had his pencil gone? Had he taken it with him? He sighed- probably left it up in the coded patient's room.

oOo

The consulting detective was pacing, his hands were steepled beneath his chin as if in prayer. The office was a typical academic's room- book-lined, with filing cabinets and a large white board on one wall. The board was covered with a mixture of mathematic equations and chemical notations. John watched as the consulting detective walked back and forth between the white board and the door. Occasionally, his hands would come apart and make odd gestures.

The other occupant of the room looked a little concerned. "Is he alright, Doctor Watson?" The man's Russian accent was still detectable beneath his English.

"Yes, Professor Novoselov. This is how he thinks."

The professor tutted. "Please, you are not a student; call me Kostya."

The doctor smiled to reassure the physicist, who seemed entirely too young to be a Nobel Prize winner. The medal had been awarded two years ago, and was the reason why Sherlock was here. The medal had been stolen, and the Manchester police had no clues at all. The University's own security systems were not particularly brilliant. ("_Idiots, John. They seem more concerned about student bicycle theft than they do with the potential for intellectual property crime against one of the finest minds of the twenty first century.")_

It took a lot for Sherlock to be impressed by someone, but he was by Sir Konstantin Novoselov, a physicist who started his career in Russia, moved to Holland to do graduate work and then ended up in Manchester, working alongside his fellow Nobel Prize winner, Professor Andre Geim. On the train up from London, John had been an audience of one for a lecture.

"He's a physicist who is also an Honorary Fellow of the Royal Society of Chemists. Absolutely ground breaking stuff, John. Over ninety peer-reviewed research papers on fascinating subjects, like mesoscopic superconductivity. But unlike an ivory tower academic, he's also capable of seeing the applicability of it all. I read his paper on gecko tape and it was just riveting."

"Gecko tape? What's that? It sounds like some...I don't know, something like that Gorilla Glue you used to fix the shower head at Baker Street."

Sherlock looked down his nose at John. "Really, John, I know medicine is an _applied_ science, but you really did specialise too early. Gecko tape is synthetic setae, a dry adhesive that first used polyimide fibers stuck to scotch tape. It mimics the unique process that allows a gecko to climb a wall, only it's much, much better at it. It was discovered by Novoselov in 2000; now they've moved on to use carbon nanotubes. It has applications in everything from nanotechnology to joint replacements."

"Is that what he got the Nobel prize for?"

"Oh, no. _That_ was for something _really__ e_xciting- his work on graphene."

John's face must have betrayed his confusion.

Sherlock rolled his eyes. "Really, John, when you were in Afghanistan did you just put your brain into cold storage? It's just the most important scientific discovery of the century."

John sighed. _That's me relegated to the back of the classroom. _"Before starting on another long lecture, Sherlock, please remember we have only ten minutes before arriving at Manchester Piccadilly station."

The brunet narrowed his eyes. "Alright then, one crash course. Graphene is an isolated single isolated atomic plane of graphite. Think of a sheet composed of carbon that is only one atom thick; it's so thin that it is effectively _two_ dimensional. Its hexagonal crystalline structures make it look like chicken-wire under an electron microscope. It's a superconductor of electricity, and it's the strongest material ever known. It will be the basis of almost all integrated circuits of the future. It can be used in everything from desalination plants to solar cells."

John looked a little sceptical. "That sounds...like a little too good to be true?"

Sherlock shook his head. "Let's just bring it closer to your comfort zone, _doctor_." He didn't disguise his sarcasm. "Graphene has a molecularly gatable structure, which makes it perfect for microbial detection and diagnosis, so even in general medicine there will be huge benefits. They are already talking about using it to serve as an artificial retina; just think, John, of the consequences for all those blind people out there in the world."

While John was trying to wrap his head around that idea, Sherlock continued. "For me, personally, the great advantage is that it will speed up and reduce the cost of electronic DNA sequencing- the backbone of modern forensics- oh, and that's also likely to help medical professionals beat diseases that have baffled your lot for centuries."

John decided that he was impressed. And looking now at the 38 year old professor who was watching Sherlock pace, the doctor decided that it now mattered more to him that the medal should be recovered.

To buy more time for Sherlock to consult his mind palace, John decided to ask the Professor about the medal. "What is the actual medal like?"

Kostya shrugged. "A lot less exciting than what it means, if you think about it. What a lot of people don't realise is that _two _medals are given- one that's solid gold, which the Prize Committee assume you will put in a vault somewhere -and I did do by the way- and then another one that's bronze, which is for public display or actually wearing, if one goes to that sort of event, which I don't." He looked down with a grin at his tee shirt, jeans and trainers.

"In both cases, the medals are only 66 millimeters in diameter- so a bit over two and half inches for you Brits- I know that you don't think in millimeters. Not very thick- each year varies in width depending on the value of gold at the time it is struck. Since 2008, the gold medals are no longer 24 carat gold- it's 18 carat on the inside, just plated with 24 carat. Maybe the thief thought the medal in the cabinet was gold? But if so, it's weird. I mean both my bronze version and the one for Andre Geim were displayed side by side in the cabinet in the faculty senior common room, but they only took mine."

Sherlock stopped in mid-stride and turned to the professor. "You said you think a sheet of your work might have been stolen on the same night. Can you tell me more? What was on it? What did it look like? Can I see it?"

Here the Russian looked embarrassed. "Well, I am not sure that it was stolen. It disappeared that night, but it could have been…misplaced. I'm a little chaotic when I am working on things in draft." He gestured to the wall. "The university installed this smartboard for me, but I really prefer to use paper and pencil. So, the day after the medal was stolen, I realised the last sheet of my current project was gone."

He gave a little laugh. "It's not even very exciting stuff- certainly not worth stealing; it's just an elaboration of something that is already out there in the public domain, so…on second thought, I don't think anyone would actually steal it."

He unlocked his desk drawer and pulled a file out, opened it and handed over some sheets of white foolscap pad pages, with very faint pencil scribbles. Sherlock took the last sheet and laid it on the desk, and then got his pocket magnifier out. He bent over the desk, looked at the writing it for a few seconds and then stood up straight again with a puzzled look on his face.

"Professor, why do you make your own pencils?"

Kastya grinned. "How do you know that? No one has ever realised that before."

"Graphite in pencils is mixed with clay. The carbon composition allows transfer; the clay makes it harder, so it will hold a point. _This_ writing has been done with a pencil that is harder than a 10H, which is the hardest availble. Is it…what I think it is?"

"You're right. I use a graphene residue, rather than just plain graphite. There is just enough graphene in the graphite mix to give it the hardness needed to be used as pencil lead, so I don't mix it with clay. Call it a conceit of mine."

"OH!" This was whispered. Sherlock's hands were brought together under his chin as if in prayer. Then decisively, the detective began to explain. "Stealing the medal is a decoy, professor; someone is after your residue. It's not about what you wrote; it's about what you wrote it with- your special pencil! And the thief hoped that in the furore over the theft of the medal you wouldn't notice that the sheet was missing. Presumably, your graphene is leftover from your manufacturing process?"

"Yes, but it's not difficult to manufacture graphene anymore, there are dozens of companies that do it commercially now."

"But not the way _you_ did it."

"Well, I suppose not. I use the residue from my very first experiments in my pencils and that was secret. Does that matter?"

"Oh, yes, indeed; it matters a _great _deal."

Now Sherlock started pacing again. "Just three months ago, the EU awarded Professor Jari Kinaret from Sweden's Chalmers University a grant worth €1 billion, am I right?"

"Yes, of course. We're one of the universities involved in the consortium winning the FET funding. There are over 126 projects involved."

"Did you get what you wanted?"

Kostya looked a little sheepish. "Actually, we got more. We were awarded €54 million. It was a bit awkward really as both Andre and I are on the Strategic Advisory Council advising the management team about the fifteen work packages involved."

Sherlock's smile was beginning to blossom. "And who was left out of that research funding?"

The professor tilted his head curiously. "Why does that matter?"

"Oh, it provides _motive_."

The professor gave it some thought. "Actually, it's the Koreans who were the biggest 'losers' if you put it that way. I mean, it's EU money, so the awarding team tended to have a European bias. The decision was made to exclude companies and organisations that are involved in graphene screen production. I mean, it's pretty much the basic start of manufacturing; the harder research work needed now is in applications. The Koreans are the leading manufacturers, Samsung in particular."

Sherlock's smile was now broad. "I don't suppose you have any graduate students from Korea here, do you?"

"Um, as a matter of fact, we do- Joon Park and Pak Soon, both brilliant graduates of Sungkyunkwan University and involved in our work here."

"Then I suggest that the Manchester Police and your University Security arrest the pair and search their premises very carefully. If we've managed to catch them before they could send the sheet of your notes back home, then your secrets will be preserved. No doubt, somewhere in their safe keeping will also be found the medal."

Three hours later, Sherlock smiled again when their train pulled into Euston Station. He showed John the text he'd just received.

**6.12pm You were right! Medal and work recovered. One of my *pencils* is on its way to you in thanks. Kostya**

* * *

**Author's Note:** * In 1989, which is when Sherlock was in the clinic, there were only 103 elements discovered. Since then another 20 have been added to the Periodic Table. Graphene is real, as are Professors Novoselov and Geim, both 2010 Nobel Prize winners. The €1 billion funding is real, too; the European Commission committed to support major scientific initiatives on Graphene over a period of 10 years- under the_ Future and Emerging Technologies (FET) Flagship Projects. _If you think silicon stimulated the growth of computing and mobile telephony, wait until you see what graphene is going to do!


	12. Chapter 12

**Carbon **

* * *

**Part Two Diamonds**

_The most well-known allotrope of carbon. The hardness and high dispersion of light of diamond make it useful for both industrial applications and jewellery. Diamond is the hardest known natural__ mineral._

* * *

"Are you really sure that you want me to sell it? It seems such a shame after all the time it has been in the family." The solicitor sighed. He looked at the photograph of the diamond tiara on his desk. His wife would have thought that such an exquisite piece of nineteenth century craftsmanship worth a king's ransom. The valuation made in 1969 said that it was worth £20,000; in today's money that was over £325,000. And the history of it, too- French-made but worn at Queen Victoria's diamond jubilee? This was a history that could not be bought. At auction now it would probably sell for a lot more.

Mycroft decided to let a little irritation show. "It was your explanation of the phrase 'asset rich, cash poor' that led me to this decision, Mr Harris. As you so eloquently said ten days ago, if I have expenses that need to be paid, then something needs to be sold."

"Yes, yes- of course, but I was thinking more of something like one of the share portfolios, or some of the financial investments."

"Any of those would probably attract the attention of my father, because he will still have access to my tax returns this year, given the inheritance. I would not welcome the scrutiny about the liquidation of any financial investments at this particular moment."

Mycroft gestured to the photograph. "He has never even known about the extent of my mother's jewellery collection. That particular item's been in the Sherrinford vaults for over thirty years and never been worn; it was made for my great grandmother. There is an auction coming up in the next month at Christie's; I've already instructed them about it and they are awaiting delivery so it can be photographed for their catalogue."

Simon Harris nodded. "Yes, of course. I will arrange to have it sent."

"Mr Harris."

There was something in the firm tone of voice of the young man sitting in front of him that made the solicitor look up sharply. He had first met Mycroft Holmes eight months ago, when he and his mother retained his services. He was so _not_ from the Holmes' family's London law firm.

He now looked into the cool blue eyes of the eighteen year old across the desk, giving him the attention that he clearly wanted.

"My mother and I instructed you originally to look after my interests when I inherited at her death, and when I turned eighteen six weeks ago. The assets in my mother's will have now been separated from my father's estate. I have no doubt that his law firm and his financial advisers will not have been pleased with that fact, and I am certain that my father is not happy either. I expect absolute confidentiality from you in this matter. Christie's has been instructed to list the item from an anonymous owner."

"I have other business we need to turn to now. Within the week, I would like you to draw up a draft of my own will. In the event of my death, my brother Sherlock is to inherit and he is to have whatever legal protection is possible from my father so long as he is a minor. My will needs to ensure that my father will have no say at all in this."

Simon gave the young man a cautious smile. "You are a little _young_ to be considering a will, but I agree it is always sensible to be prepared."

Mycroft just ignore him and carried on. He'd clearly thought it all through. "In accordance with her wishes, I will be moving a portion of her inheritance to Sherlock. Trust funds and independent trustees will be needed. Before that happens, to protect his interests, I have need of accessible funds, in part to pay your bills- hence the sale of the tiara. I know for a fact that my mother would approve of selling her diamonds to protect someone who was more important to her than any diamonds- her younger son."

"Given my family situation, it is essential that I help my brother. That is also why I also need to understand if it is possible to get some form of legal responsibility- perhaps guardianship- of my brother, even while my father is still alive. I'd like you to investigate what options are open on that front. It is possible that even after he reaches the age of eighteen he will still be classified as a vulnerable adult requiring guardianship."

The Oxford solicitor had wondered at the mother and son bringing their business to him. It had been on the clear instructions that it was to be kept confidential from Richard Holmes. _A family dispute, and now a custody battle over a vulnerable child? Ouch, that could be expensive! _

Looking at the firm set of the young man's jaw and his air of utter determination, the solicitor had no doubt that Mycroft Holmes was as hard as the diamonds he was now selling.

0oO

Antoine Maes was sweating and flushed, clearly stressed and anxiously twisting a knotted handkerchief in his hands. John had answered the door and brought the client up, while Sherlock finished one of his experiments and then swept the morning newspaper off the sofa. Now seated on it and supplied with a cup of tea by the doctor, the Belgian was looking like he had no idea where to begin.

Sherlock decided to help. "You've come to London today, but I can tell by the creases in your trousers that it was not on the Eurostar from Brussels. You flew instead. Perhaps the 7.12 departure to City Airport? Mr Maes, your business is clearly too confidential and urgent to trust to a phone conversation or e mail. Start at the beginning, but do try to avoid being boring with the details. Just the facts."

"Please to forgive my English, _Monsieur_ Holmes. It is not my first or even second language." The words were delivered in a very thick French accent.

Sherlock nodded. "I am fluent in French, but alas my colleague Doctor Watson is not, so just do the best you can, for his sake."

John had opened his laptop to make a few case notes, and he now shot a look at the consulting detective for that comment. He could not compete with the eleven languages that Sherlock managed, and few clients came to Baker Street requiring his working knowledge of Pashto. Still, no need to be insulting.

"Well, _Monsieur, _the problem is this." He unknotted the handkerchief and handed over a walnut sized object.

To John's eye, it looked like a piece of glass. Sherlock took the object and walked over to the window, holding it up to the light. "Oh! A blue diamond. Rare, about twenty carats in weight. Radiant cut- has 77 facets instead of the Brilliant cut's 55 facets." He then looked back at the Belgian.

"I see your problem. How did it come into your possession?"

"That is _ze_ problem, _Monsieur_ Holmes. It is most _extraordinaire_! My wife bit into one of my chocolates and _voila-_ this was what was inside! She thought it the most romantic birthday present ever. But of course, I had never seen it before. I am a chocolatier by profession. I make the box of chocolates for her especial every year. I know that it was not in the chocolate, because I make each one myself; it is not possible."

John thought it the most bizarre story. How on earth could a diamond that size end up in a piece of candy?

A smile of amusement began to form on the detective's face. "Yes, this could be very awkward for you, _Monsieur_ Maes. Your chocolate shop is at the Brussels airport?"

"_Oui_, you understand my dilemma now."

"Of course."

John was confused. "Well, I don't. If something so valuable turned up in one of your chocolates, why didn't you go to the police about it?"

"Of course not! It would be my ruin. They would never believe me. Only last night the shop was broken into, ransacked, chocolates everywhere. I am distraught! The police have been investigating – so suspicious. The whole thing is ..impossible! My reputation will be ruined. I just wish this diamond to be returned to its rightful owner, quietly. Is this something you could do for me?"

Sherlock looked at him speculatively. "Oh, I think I can do _better_ than that."

John was getting annoyed at being left out. The detective and the chocolate were speaking English, but it still made no sense to him. "A little translation here would be appreciated, Sherlock."

The consulting detective stopped his pacing. "Three days ago, on the 19th of February at 8pm, a gang of eight men dressed as airport security cut a hole in the perimeter fence at Brussels airport, and hijacked a KLM van. They drove it to a Helvetica passenger plane bound for Zurich that was being loaded with cargo- a rather special cargo. Without the passengers even being made aware of it, they proceeded to steal some boxes that had just been loaded into the hold by a Brinks security van. In those parcels were diamonds, worth an estimated £30 million. Six minutes later, they were gone. "

"_Exactement_! _Ze_ _aeroport_ police went berserk. Searching everywhere. There are over one hundred shops, restaurants, services at the airport, but each was searched thoroughly. I myself was interrogated, even though I was at home at the time. My shop is open until 9pm each night for the late passenger flights, but my assistant was on duty."

The detective steepled his hands under his chin. His eyes glittering like the diamond he had just handed to John. It was enormous, and shockingly blue. He looked up as the brunet started his deductive stream of consciousness. "There can be no doubt that this diamond is part of the stolen consignment. A blue diamond this size is worth somewhere in the region of 5 million euros- a suitable payment for someone willing to give the raiders inside information. It is more convenient than cash, more easily hidden. You trust your assistant?"

"With my life, Monsieur! Our families have known each other for years; we grew up together. No, not in a million years would I suspect Jean."

"Did you leave him on duty today? Phone him now and ask him if a colleague from the Antwerp Diamond & Jewels shop at the airport asked him to make a special box of chocolates. It is possible that he knew he would need a safe hiding place, and used your chocolates for just that. A mix up in the fridge, you grabbed the wrong box on way home, and the mistake becomes evident. I hope your wife didn't break a tooth. Diamonds are very _hard_ for a centre filling of a chocolate."

The call was made. Rapid fire French ensued. Mr Maes' eyes grew large, than his face angry. When he ended the call and put his phone back in his pocket, he used the handkerchief to mop his face.

"It is as you said, _Monsieur_ Holmes. The night manager at the Antwerp shop, Dirk Aalbers ordered a special ballotine of truffles to be made. He asked Jean if he could choose them on the night of the 19th; he knew he would have no time tonight when he was on his way home to celebrate his wife's anniversary."

"So, _Monsieur_ Maes, you have your answer. Aalbers must have slipped the diamond into the middle of the chocolate without your man noticing, and then they were put back into the fridge to be collected the next day. Your wife's box and his must have been mixed up; he was given the wrong one and the rest you know."

Sherlock took the jewel from John and held the diamond to the light of the window again. "I will return this to the rightful owners and advise the Belgian authorities to arrest Mr Aalbers. I believe that I can ensure your assistance can be kept confidential from the authorities- there is no need for publicity."

"_Mon dieu_! _Merci_, _Monsieur_ Holmes. I can never thank you enough."

When John showed the smiling Belgian down the stairs, the doctor stopped him at the door. "Could I make suggestion, Mister Maes? Perhaps you would like to visit the duty free shop at City Airport and select a nice piece of English jewellery for your wife?"

That brought another beaming smile. "Ah, _oui_, Doctor Watson! That is excellent advice!"

* * *

**Author's Note**: the theft is real- took place on Feb 19, 2013 from Brussels airport. This is a nod to ACD canon and the blue carbuncle.


	13. Chapter 13

**Periodic Tales Chapter Thirteen**

**Part Three Amorphous Carbon **

_aC is free, reactive carbon that does not have any crystalline structure, unlike graphite and diamond. It is the name used for coal, soot, charcoal. Activated carbon (also known as activated charcoal) is processed into powder to increase the number of small, low volume pores, increasing the surface area available for adsorption or chemical reactions. It is the principal method of emergency department medical treatment for particular forms of poisoning. _

* * *

Sherlock squeezed his eyes shut. The light was bothering him even more than normal. He'd woken up with that awful buzzing, the dull thud of his pulse loud in his ears, the sense that everything in his head felt raw and aching. By now he knew why he felt that way, but it didn't make it any easier to bear. It's whatever happened in the place they took him to, after the mask. At first, he fought when they took him away from the ward, but then they started tying his hands to the metal bars of the bed so they could push the mask onto his face. The horrible scent and the texture of whatever it was they made him breathe made him want to throw up. He'd tried holding his breath, but they just waited until he couldn't hold it any more. Then just as he would start to lose his sense of where he was and what was happening, he'd feel the trolley being moved. But, he'd never managed to stay awake long enough to know where they took him or what they did.

All he knew is what he felt like when he woke up- which was awful. And whatever they did to him made him forget things, important things. He was finding it hard now to remember what Mummy looked like, what her voice sounded like. He had to look at the pencil marks in the back of his book to know what the day was. And each time he tested himself on the periodic table, he found something more wasn't there.

It was a different kind of forgetting. Not like misplacing something, where if he thought hard and long enough, the memory would come back. No-he lost things permanently. That meant starting over again, learning the elements one by one, filling in the missing gaps with stuff he'd forgotten. Lately, it was getting worse. If it had not been for the chart and the empty boxes, he would not even know that he'd forgotten some of the elements. That scared him. Not the kind of little anxiety that Mummy used to talk to him about, that made his hands flap or which he could soothe by rocking. This loss was big, almost as big as losing Mummy. She wasn't coming back, and he was afraid that whatever happened in that room was going to take everything away, so he wouldn't even know what the boxes on the paper were for, or how to start filling them in again.

The doctor came to visit every other day, repeating his silly tests. The man tried to get him to talk, and Sherlock never did. He wouldn't look at him, or even show that he had heard him speak or ask a question.

Because he never spoke, the staff seemed to forget that he could listen and understand what they said. So, he spent a lot of time listening. When the night nurse came back, Sherlock heard the temporary one telling the other one what had happened while she was away. She told the older woman how one of the teenage patients on the floor above had killed himself by taking all of his pills at once. He'd hidden them, fooled the nurses into thinking that he'd taken them when instead he hid them away.

Before he heard the two women talking, it had never occurred to Sherlock to do that, to hide the pills. So, he tried it the next day. And it worked. The nurse always made him open his mouth to show he had swallowed it, but this time he hadn't. She didn't realise that he had put the tablet into the place between his lip and teeth. As soon as she was gone, he took it out of his mouth, dried it on the sheet and put it into a little tube he made out of one the sheets of paper he'd stolen. He stuffed the tube into the space formed by the spinal binding of his book. When he'd been to the room again, and he forgot about the pills, he found them when he opened the book, and remembered why he was collecting them.

The book was his lifeline now. He stopped letting the nurses read to him from it. He just kept the book in his hands when they were near, and wouldn't let them take it. They stopped trying, which was good because then they wouldn't find the tablets, his pencil marks for dates and the loose sheets with his attempts to complete the periodic table.

That afternoon, when he woke up and realised that he'd been to the room again, Sherlock decided that he had to find out how much he'd forgotten. In the quiet period after the evening meal, he opened the book and kept it tilted up on his knees, so that a nurse would only see that he was reading. He opened it to the pages where he had inserted the loose sheets with his previous attempts at completing the grid. There was only one blank grid left. He hid his hand with the pencil behind the book so a nurse wouldn't see what he was doing. He filled in the boxes he could remember, and then counted- 34 of the 103 boxes had letters and numbers; the rest were blank.

Sherlock went back through each of the earlier grids. Three weeks ago, he'd managed 58. Six weeks ago, it was 72. The first grid had 89. He knew what it meant. He couldn't re-learn fast enough to keep up with whatever was being taken out of his memory by the trips to that room. He couldn't pretend it was going to get better. The doctor who smiled at him and said "you're getting better" was _lying_.

When the lights were dimmed, and the rest of the ward patients started to go to sleep, Sherlock pulled his book under the sheet and took out the tube. He counted the tablets- seventeen of them. Would it be enough? He didn't know. He hoped so.

He started to chew. The first two tasted revolting- so bitter. They made him want to choke so he just swallowed and tried not to cough. He chomped up three more and then reached for the plastic cup of water on his bedside cabinet. Using the water to push the bits down his throat helped. But, he didn't have enough water. He'd finished only ten before the cup was empty. Dare he ask the nurse for more? He'd never done that before, they might ask why, and he would not be able to answer. _Where else can I get water?_

He stuffed the tube with the seven remaining tablets into his pants, and banged the bars of his bed. That got the nurse's attention and she came over from her chair at the end of the ward.

"What is it, Sherlock? Are you alright?"

He gestured to the front of his pyjamas and then down the corridor to the bathroom. It was the signal he'd used to indicate that he needed to go to the toilet. She lowered the bars on one side of the bed and he got down, putting his dressing gown on. She knew better than to touch him, but followed him to the loo. When they got there, he didn't go to the urinal, but rather into one of the stalls, and shut the door. He looked at the water in the toilet bowl, fumbled with the tube and stuffed all seven of the pills into his mouth, chewing them up into smaller bits, fighting against the bitterness that made him want to gag. He reached down with a hand into the bowl, and scooped up some water into his mouth, trying to muffle the sound as best he could.

Ninety minutes later, the ambulance came and took a critically-ill ten year old boy to the Emergency Department of Bethlem Royal Hospital.

"Tricyclic antidepressant overdose- that's what the doctors at the clinic think; the patient didn't have access to anything else. Tachycardic, confusion, agitation and hallucinations. He had a seizure in the rig. He's in respiratory distress."

"Any vomiting?" The ED team's senior doctor asked quietly as the still form of the thin boy was transferred to the table in the trauma room.

"Nothing reported."

The doctor frowned at the heart monitor. The boy's oxygen levels were too low, his breathing too erratic.

"Intubate." And then another tube went down, this one into his stomach. "How long ago did the symptoms first appear?"

"According to the ward nurse there, he must have ingested the tablets at about 8pm, when he went to the loo."

"OK, too late for gastric lavage, but we're just within the window for activated charcoal and IV sodium bicarbonate. Let's move, people."

It took them a while, but the black liquid did its job. The symptoms eased a bit, and the boy's heart function stabilised long enough to move him to the ICU. A doctor from the clinic arrived not long afterwards to check on the patient; Doctor Molhotra said that the clinic had tried to contact the boy's father, but been told that he was overseas on a business trip and the housekeeper did not have a contact number. She would try to get it in the morning, when Mr Holmes' business office opened at 9. Dr Molhotra asked to be kept informed about the boy's progress, and went back to the clinic.

Overnight, the ICU staff kept a watchful eye on Sherlock's blood pressure, temperature, arterial PH; he remained intubated, and on IV fluids. The ECG monitor was watched at regular intervals for any abnormal rhthyms. The next morning at 7:12, the boy briefly recovered consciousness but would not speak or show any signs of understanding what was being said to him, so a specialist was called to the ICU for a consult. The junior doctor presented the case and handed the new patient's chart to the petite, dark-haired doctor.

She read the first line on the chart, and shot a startled look at the still figure in the bed.

"Bloody hell."

She reached for the phone on the wall, and got the hospital switchboard. "I need to make a call to Oxford University. Can you find a number, and get someone in authority at Balliol College to find Mycroft Holmes immediately and get him to call me here at the ICU. It's about a patient that has just been admitted. As quick as you can, please."

oOo

Sherlock paced as he explained, hands gesturing and making strange shapes as he spoke. "This is murder, Lestrade, not suicide."

John's verdict was strychnine poisoning, based on his initial examination of the body, but he didn't have a view about how it had happened; he left that to Sherlock.

"Holmes, don't be an idiot. She's lying in her bed, a vial of the poison beside her and a typewritten note underneath it that says she can't face the cancer. What more do you need?" Anderson's face was red and angry. Before Sherlock arrived, he'd pronounced on the death, saying it was suicide. The grieving widower was at the next door neighbour's house, being comforted by a sixty year old lady who was a friend; they'd spent the afternoon on a gardening club visit, only finding his dead wife when he returned at dusk.

The consulting detective just scowled at the Crime Scene Examiner. "Don't…just don't be such a simpleton, Anderson. It's clear that this is exactly what the husband wants you to think, and like some lemming, you leap off the deductive cliff in sheer stupidity."

The forensic officer came up to Sherlock, leaned into his personal space, and just let rip. "For God's sake, Holmes, why do you have to complicate everything? She's an elderly woman diagnosed with a terminal cancer. Rather than face a long slow death, she opted for a quick exit to spare herself and her husband. We found the box of mole poison in the garden shed. She picks a time when he's out for the afternoon with the gardening club. For once in your life, just accept that not every crime needs someone as compulsively fixated as you are to solve it. You can't deny the evidence."

Sherlock drew in a deep breath and was about to let fly when Lestrade stepped in between the two men, as if he were a referee in a boxing match. "Alright you two, just back into your respective corners." He watched as Anderson stepped away, muttering in disgust.

"Sherlock, you have to admit, this looks like an open and shut case of suicide." The Met detective inspector's disbelief was tangible.

"Exactly! That's the point; it's manufactured so idiots like you all will draw the obvious conclusion and not look any further. This was _planned_ well in advance. The husband bought two identical tea pots with matching mugs, so that the one in the kitchen will test clean. If you look carefully- either in the rubbish or maybe buried in the compost bin- you'll find the broken bits of china, which will test positive for the poison. He infused the herbal tea, laced it with strychnine. Then set up the camera to film the 'tea party' for the benefit of their daughter in Toronto, to whom he sends the video. He has his alibi, they drink the tea, and all seems well in the world."

The brunet was now pacing again. "He sends the wife upstairs to rest, and then the symptoms emerge. Strychnine takes ten to twenty minutes after exposure to start taking effect- the muscles in the neck start to spasm, then the contractions spread to the rest of the body. She goes into almost continuous convulsions, and then she gets lactic acidosis, the respiratory system is paralysed and she dies of asphyxiation. It's a horrible death, takes two to three hours in total- which gives the husband all the time he needs to dispose of the evidence, and then go next door to be seen with his neighbour at the time of the actual death. When he finds her dead, the husband puts the note and the bottle there and calls the doctor."

Lestrade crossed his arms. "Sherlock, we have the video- there are _two_ of them drinking the tea- so how come he doesn't succumb?"

"John, look in the conservatory. Bring me the box of activated charcoal that is sitting alongside the aquarium. It's been hidden in plain sight, because the husband knows that forensic people are too thick to think beyond the obvious."

The doctor looked dubious, but left the living room and headed for the conservatory.

"Lestrade, the husband is the killer. In a matter of hours, he will excrete the neutralised poison. He will have consumed a drink of activated charcoal probably laced with sorbitol so the poison would be adsorbed and then excreted faster, to minimise its effects. The charcoal protects the whole of the GI tract, so that the poison is never ingested. It's the perfect alibi, and designed to fool people who look without understanding the evidence."

John returned with the box of aquarium charcoal. Sherlock tipped it out onto the table- a fine power spilled onto the white tablecloth. "Look, and this time _see_- aquarium charcoal is normally small lumps, designed to remove impurities from the recirculated oxygen. This is medicinal grade activated charcoal used in Emergency Departments. Anderson, as you clearly do not believe me, go bring Mr Trevelyan here. John, another treasure hunt for you- next to the aquarium you will find a toothbrush that has been blackened- and in the bathroom upstairs will be a new toothbrush next to an old one used by his wife."

John was used to being ordered about like this by Sherlock. While it still annoyed him at times, the consulting detective's peremptory tone made Anderson bristle. "Really, Detective Inspector, being ordered about like some lackey by Holmes is just not acceptable."

Lestrade looked at the Forensic Officer. "Yeah, well, if he didn't have such a record of being right almost all the time, I might agree, Anderson. Do me a favour, and just go get the guy, will you?"

John returned carrying two toothbrushes just as Mr Trevelyan and Anderson came into the room.

Sherlock held up the blackened toothbrush in front of the pensioner. "Mr Trevelyan. Would you care to explain how in 1831 Professor Touery managed to astonish his colleagues at the French Academy of Medicine, when he drank a lethal dose of strychnine and lived to tell the tale?"

The old man looked confused. "I don't understand."

"Then please let Doctor Watson take a good look inside your mouth. No matter how well you brushed your teeth, there will still be stains from the activated charcoal you used to protect yourself when you drank the same tea that killed your wife. So, open wide…"

The old man looked at the faces of the other men in the room, and then his shoulders crumpled in defeat. He opened his mouth to expose his blackened teeth. Trevelyan then confessed to killing her.

"I put her out of her misery. I could not face the prospect of watching my wife decline into such a horrible death. I wanted to ease her suffering."

"Oh, I don't think that explanation will wash with a jury, do you Mr Tevelyan? Especially after the prosecution proves that you've been having an affair for years with your neighbour. You couldn't stand the idea of your wife's nursing care eating up your limited resources, so you poisoned her. Once you get life insurance pay-out, you and your neighbour are off together to sunnier climes." The consulting detective pointed to the pile of world cruise brochures on the coffee table.

Anderson was still scowling as the pensioner was taken away. Sherlock looked smug. "John, there are some poisons that charcoal cannot purify; greed and lust are two of them."


	14. Chapter 14

**Periodic Tales Chapter Fourteen**

**Caesium Cs 55 132.9049**

An alkali metal which is soft, silvery-gold in colour with a melting point of 28 °C (82 °F), which makes it one of only five elemental metals that are liquid at (or near) room temperature. It is highly reactive, igniting spontaneously in air, and it reacts explosively with water even at low temperatures.

* * *

John was sitting at the table, Sherlock was in his chair. It was pouring rain outside, so both of the men were working on their respective blogs.

"Sherlock."

No reply, so John tried again.

"Sherlock, you have a fan."

"Hmmm?"

The consulting detective did not look up; but kept typing in his furious pace. It was just one of the things that Sherlock did so much better than John, who had never managed to use more than four of his ten fingers when typing. John tried not to be jealous of his flatmate's manual dexterity.

"She – or maybe he- not easy to tell from the tumblr name- just posted a question on my blog. Wants to know what colour your eyes are."

John watched the furrows appear on either side of Sherlock's brows.

"Why?"

"Apparently, there is some debate about it."

The brunet snorted. "My passport says 'blue'."

Now it was John's turn to snort in derision. "No, Sherlock. _My _eyes are blue. So are Mycroft's. Yours are something else. Grey? Silver? Green? I don't know…you tell me. The person posting on my blog says your eye colour changes like some sort of chameleon- or an alien."

Sherlock finally looked up from his own laptop and scowled. Right now John would call the colour of his flatmate's eyes 'stormy'.

"You realise that eye colour is …a rather complicated subject? The presence of certain proteins in the melanocyte cells are the basic ingredients of everyone's eye colour, and the distribution of it in each iris is unique. Everyone's eyes have a different mix of pigments in different places in the iris, and each eye is different. I have a spot of brown in my right eye near the pupil, but it's not there in my left eye. Iris recognition systems are based on those facts. "

John looked down at his keyboard, as if considering how to translate that into a simple answer.

Sherlock sighed. "John, just tell her the science. There is no such thing as blue or green pigmentation in an eye. That's the effect of the scattering of light through the two layers of iris cells- the same way the sky is thought to be blue, when it isn't, actually _blue_.

"So, what do you suggest I say in my reply to her question-'none of the above'?"

"My mother once used a French term for the colour of my eyes – _glasz_. That's not spelled like glass by the way; it has a final zed not a second s; it's a Breton word and relates to the colour of the sea. Personally, I prefer to use the chemistry definition."

Now John looked even more perplexed.

"In 1860, a German chemist Robert Bunsen – yes, the Bunsen burner is named after him- and a physicist colleague, Gustav Kirchhoff, used a spectroscope for the first time to discover a new element. It produced two blue lines that no one had ever seen before; they called it _caesium_ after the Latin Word for 'heavenly blue'.

Smirking, he returned to typing on his laptop.

John began to type.

oOo

Just under four hours after receiving a phone call from the Royal Bethlem Hospital, Mycroft Holmes walked into the reception area of the Mount Sinai Rehabilitation clinic. His journey had taken him from Oxford to Paddington Station, then across London to Victoria Station and then out by train again to Bromley South, then finally a taxi to the clinic He asked at the front desk for Doctor Esther Cohen.

"Oh, yes- you must be Mr Holmes. Please take a seat while I page her."

He looked around the reception area, with its comfortable seating and potted plants. The three storey modern building was in a small clearing, surrounded by trees and ringed with flower beds. Light, clean and airy, the large plate glass windows let sunshine in. It didn't feel like a hospital.

He watched as a young couple with a small child gathered around an elderly woman sitting in the garden enjoying the afternoon sunshine. _Happy family; doting grandmother. _From the way she was sitting on the bench, he decided she was recovering from either a broken hip or a hip replacement- hard to tell at this distance. For some reason, it made him think about his grandmother, Sophia.

"Hello, Mycroft."

"Doctor Cohen." He stood and shook hands with the small woman. Her eyes were sparkling and she smiled broadly.

"How is he?"

"Recovering. I sedated him at the hospital, so the move wouldn't distress him. He's still asleep."

For a moment, neither of them spoke, as if unsure where to begin. Another patient came by, this one in a wheel-chair, being pushed by an attendant.

"The patients here seem to be ….rather older than I expected."

Esther stifled a giggle. "Yes, well- that's because it's a private geriatric rehabilitation unit, run by my uncle: forty beds for the wealthy Jewish widows of south London. I think it was growing up with this in the family that made me want to do paediatrics, to be honest. But, family is useful in times of need, and Uncle Harold was willing to do me a favour on short notice. Your brother was admitted under the name of Shirley Cohen. I doubt your father will be able to figure it out. I managed to get Sherlock moved before Bethlem hospital was able to get in touch with him in the Far East. It's all legal, by the way. In the absence of a parent, another adult family member is able to issue instructions, so the hospital discharge papers are all in order. I got the Emergency Department to tell Doctor Molhotra that the family has decided that Sherlock won't be coming back to the King's Court Clinic, given the circumstances. So, we have a little time before deciding what to do next."

"I want to thank you, Doctor Cohen, for finding my brother."

She shook her head. "I didn't _find _him; he found me. We have to chalk this one up to coincidence and serendipity. The clinic he was at- Kings Court Clinic in Orpington- brings its emergency cases to Bethlem, and I just happened to be the duty doctor this morning."

"However it happened, it means he's safe now. Can I see him, please?"

She smiled again. "Of course."

On the second floor, at the end of the corridor, she stopped in front of a closed door. "Before we go in, I should tell you what I've been able to get from the admission team about what happened. Sherlock was being treated for depression, and he horded the drugs until he could take an overdose. Ten's a little young for purposive suicide, but there is no doubt that he knew what he was doing. Apparently, last month a teenager from the same clinic overdosed and my guess is that this was a copy-cat. According to the ED doctor the clinic said that Sherlock's not spoken a word since arriving there in January. They had him on lithium for a while, but that's been tapered off, and anti-depressants introduced instead." She stopped for a moment.

Mycroft caught the hesitation. "What is it you are finding hard to tell me, Doctor Cohen?"

She looked away for a moment, then turned her eyes back to the tall young man. "The clinic used a rather old fashioned treatment to try to break him out of a near catatonic state, and they've kept it up, too, according to what my ED colleague got out of the clinic. Have you ever heard of ECT?"

Mycroft shook his head, the initials didn't mean anything to him.

"Electroconvulsive Therapy. The patient is anaesthetised, given a muscle relaxant injection and then a brief electrical stimulus is given to the brain, using electrodes put onto the temple. The electrical impulse lasts about four seconds. It induces a seizure."

"Why?" Mycroft did not disguise his surprise.

"That's a good question, wish I had a simple answer. There are some who say it affects the way neurotransmitters work in the brain. It's used to treat severe depressions, when anti-depressants aren't working."

Mycroft picked up on her discomfort. "You don't think the treatment was warranted?"

She shrugged. "I don't _know_, do I? I have not examined your brother, not tried to speak with him or identified what is the nature of his problem or the state of his mind. I can't say for sure. If he hasn't said a word for five months, and not engaged with any therapy, then perhaps the doctors felt there was no alternative. But, for a child on the autism spectrum, I …" She hesitated again.

"It's just that there are side effects of ECT- memory loss and disorientation being the most common. That would be bad enough for a neuro-typical child. For someone who needs familiar surroundings, for whom communication is hard and social engagement difficult- well, it could drive that patient even further into themselves. So, I guess what I am saying is that he may not be the brother you knew. I can't even guarantee that he will recognise you."

_Father would know this. He would have chosen this therapy on purpose._ Mycroft looked down at the doctor. "If that happened, if the treatment only exacerbated the autistic tendencies, would that justify indefinite institutionalisation?"

She was surprised by the young man's dispassionate assessment. "Yes, I suppose it would."

Mycroft's gave her a steely look. "Then it is safe to say that my father knew this and agreed to the treatment with the express intention of doing just that."

She looked horrified. "How could a parent do that?"

"You have not met my father, Doctor Cohen. Now, can I see my brother, please?"

She opened the door and they went in. There was a heart monitor beeping quietly beside the single bed in the room. Sherlock's face on the pillow was half obscured by long dark curls. _He hasn't had a haircut since January._ Mycroft just looked at him. In repose, the lines were soft, but he could see that his brother had lost weight from the prominence of his cheekbones. His eyes were a bit sunken, the sockets dark, almost bruised.

Doctor Cohen was watching the monitor, and murmured "a good rhythm; no side effects then from the overdose. He should wake up in a couple of hours."

Mycroft smirked. "He's awake now, and listening to us. He heard our conversation outside, too. He knows it's me, but he's not too sure about you."

He looked down at the hospital bed and fumbled for a latch. Esther released it for him, so the bars could drop on his side. Mycroft then leaned down so his eyes were level with the edge of the pillow.

"She's OK, I promise. You're safe here."

There was no movement at all.

"Open your eyes, Sherlock; this isn't a dream. I've finally found you."

The dark lashes fluttered, and Mycroft found himself looking into those impossibly blue eyes. He smiled. Sherlock just looked at his brother, really _looked_.

Doctor Cohen held her breath.

"What took you so long, Myc?" The voice was a bit croaky, as If rusty from lack of use. But the words were real, and they came from the mouth of a boy who had not spoken in five months. A thin arm came out from under the sheet, and reached up, fingers splayed. Mycroft extended each of his longer fingers and then touched them to his brother's.

Esther Cohen could only think _he's got such beautiful eyes._


	15. Chapter 15

**Chapter Fifteen**

**Caesium**

_Alkali metals are highly reactive, and cesium, being one of the heaviest alkali metals, is one of the most reactive. It is highly explosive when it comes into contact with both air and water. This contact generates hydrogen gas that is heated by thermal energy that is released at the same time, which then causes ignition of the gas and a violent explosion ensues. Because cesium is so reactive, even ice can trigger an explosion._

* * *

"Mycroft, the chemistry doesn't _lie_. People do, and politicians are people- or at least they were the last time I checked. Are you suggesting that the House of Commons is now stocked with aliens who are somehow congenitally unable to lie? How did you let this happen?"

John tried to hide his smirk. When Sherlock unleashed the sarcasm, the flat became a battlefield. And no one provoked sarcasm more than the minor official in the British Government who was now gazing at his brother looking like he had just sucked on a lemon.

The two Holmes brothers were debating- _Verbal_ _fist_ _fighting? Vocal violence? Ballistic banter?_ John tried to find a less civilised word than debating, because the exchanges were getting increasingly heated and volatile.

"Really, Sherlock. Must you resort to …schoolboy taunts? Surely even a self-confessed sociopath is able to appreciate that when people panic, it is a problem." This was said with some heat. _Careful, Mycroft, or that 'Ice Man' image is going to melt_. John settled back to watch the fencing match, with barb and counter-thrust designed to draw blood.

At issue was the idea being put about in the newspapers that Chechen terrorists had stolen a significant quantity of caesium 137, and that London might be a target for a so-called 'dirty bomb'. Sherlock was dismissive. "Yes, of course it's a radioactive isotope, and it has a relatively long half-life of 30 years so if there were to be a significant exposure over a long period of time, it would be lethal for those in the immediate vicinity. But most of those would be at greater risk from the conventional blast damage."

Mycroft sighed. "Oh, do grow up! You are missing the point, Sherlock. It isn't about what is actually done; it's what uninformed people think it can do that matters. The mass panic and hysteria would be what the terrorists were trying to achieve. Even the word 'caesium' sounds scary, especially when the Sun headline writers get to work on it."

Sherlock snorted. "John, explain to my ignorant brother just how common caesium 137 is."

The doctor looked startled. "Uh…why would I know that, Sherlock? We're not all blessed with a mind palace stuffed with chemistry trivia."

Sherlock looked offended. "I am surrounded by idiots, present company included." He shook his head in frustration. "Caesium 137 is a commonly used gamma source, found in virtually every hospital in the country. It's used to calibrate the radiography equipment to treat cancer. It's considered so safe that it is used to irradiate foodstuffs to kill germs and suppress sprouting of wheat-based products. After treatment, there is no radiation or residual poisonous material. It's as safe as houses. In fact, probably more so- It's commonly used to check for cracks in industrial pipelines. If you want to really wreak havoc then your common or garden variety terrorists are going to need something other than caesium."

Sherlock waved his hand dismissively, "Even the Chechens know this. The two attempts they've had so far with a bomb involving caesium were in 1995 in Izmayolvsky Park in Moscow, and then again in Chechnya in 1998. Neither of them was actually detonated because if they had been everyone would have realised it was just a damp squib- both were just PR stunts."

The consulting detective glowered at his brother. "It's spooky to idiots because caesium 137 glows blue in the dark, like some bad horror film prop. It's not a weapon of mass destruction, Mycroft. Maybe, if the authorities mishandle it, it might be a weapon of mass _disruption_, but that would primarily be because of the panic that people like you did little to stop. The actual impact on civilian casualties from a conventional bomb is much greater."

"Unfortunately for the rest of the world, Sherlock, we are not blessed with your grasp of the chemical elements. If we were, then there would be far less scare-mongering. But until such time – and I do think we are eons away from that blessed day- then I have to deal with the real world and its shaky grasp of anything that has the adjective 'radioactive' in front of it- be it plutonium, uranium or caesium." With that, Mycroft stood up collected his umbrella and went out to do battle with those who did not know what caesium was- let alone one of its radioactive isotopes.

oOo

"You're wanted in the Master's Office, Holmes. Best be quick about it, too."

Mycroft had been expecting it for some days, after he'd estimated just how long it would take for his father to get back from the Far East, to investigate what happened at the Kings Court Clinic and to track down to paperwork regarding Sherlock's release from Bethlem Royal Hospital. So, when the Porter knocked on the Master's office door and opened it, Mycroft knew who he was going to find on the other side.

Sir Anthony Kenny was seated at his desk. But standing at the window with his back to the room was the tall commanding figure of his father, Richard Holmes.

The Master gave him a slightly strained smile. "I am sorry to have interrupted your revision seminar with Doctor Simmonds, but your father needs to speak with you urgently." He stood up and made his way around the desk. "He's also asked for privacy, so I have offered him the use of my office. I'm off to give a lecture for the next hour." As he passed, he gave the young man a concerned look, but said nothing more before leaving the room and shutting the door quietly behind him.

Mycroft waited, his hands resting on the back of the chair that was in front of the desk.

"Where is he?" The three words were delivered in a tone that spoke of a rage scarcely held in check. Mycroft could see that the back of his father's neck was flushed, beneath the man's reddish-brown hair. He had not even turned away from the window to look at his elder son.

Mycroft's reply was cool and calm. "Who?"

"Don't play the innocent, Mycroft; it doesn't suit you. Where did you put him?"

"The location doesn't actually matter, father."

That reply made the stern figure turn away from the window, to look the young man in the eye. "What are you playing at, Mycroft?"

The eighteen year old did not acknowledge his father's withering gaze. He did not rise to the bait by trying to argue that he was not _playing_ at anything. He stayed silent, waiting.

"Sit down." The command was almost growled.

"I prefer to stand, sir."

The answer was courteous. Mycroft would not give his father any additional cause for anger. He knew that he'd done enough, simply by finding Sherlock and removing him from his father's direct control.

However, his calmness seemed to infuriate the older man, who left the window and came to stand closer to his elder son. In the five months since his mother died, Mycroft had grown almost two inches in height. His father was no longer looking down at a child, but at a self-possessed young man, who didn't seemed intimidated by the older man's height and bulk.

Richard Holmes' eyes were incandescent. "Sherlock is not your responsibility. He is mine. You will tell me exactly where he is and then you will cease to interfere with what I decide is best for him."

Mycroft kept himself utterly still. He did not give any outward indication of his nerves. His answer was calm and simple. "No."

He saw his father's pupils dilate, his face contort, but the younger man did not flinch or try to dodge the slap that came. He had expected the explosion of rage, took it, and stood his ground. Then he calmly asked, "Why do you think that physical violence will make me more likely to tell you anything?"

If it had been sarcastically said, then perhaps it would have sparked another explosion. But, because his son's question was as calmly asked as if he had been enquiring about the weather, Richard Holmes was taken aback.

Subtly, something changed in their relationship. The older man was thrown off balance. This was not Mycroft, the obedient son and heir who had done everything his parents had ever asked of him, with style and grace. This was not the genius who had dazzled his peers, delighted his elders and made a point of attracting the attention of those who saw his potential.

"What's he done to you, Mycroft? Did he come begging for help from you? Made you feel guilty somehow, made you think that you owe him something? You don't. Whatever he is saying, he's trying to manipulate you, the same way he did your mother. Caring is not an advantage, Mycroft, _he_ isn't worth it. You have more important things to do than look after someone who can't look after himself. He'll never live an independent life; he needs the care of professionals who can deal with his particular kind of mental defect."

Mycroft looked curiously at his father. "And why do you think that argument has any more bearing now than it did when you said it to me at Easter?"

The ice cold tone must have startled his father, because he stepped back to look at his son, as if he'd never seen him before.

Richard tried again. "You are my son; you will obey me in this."

That made Mycroft tilt his head curiously. "or…what?"

At that moment, he watched realisation creep into his father's eyes. And then reassessment, followed by a kind of grudging recognition.

Mycroft nodded. "Yes, father, you taught me well. You always said don't fight battles you can't win."

That made his father scowl, "What makes you think you can _win_ in this case?"

Mycroft's answer was almost instantaneous. "Because you have more to lose than I do if this becomes public. Neither of us wants this to go to court. But, I have the means to do so, should it become necessary. And I have the evidence I need, too. Sherlock tried to kill himself because you abandoned him. You won't win. And public exposure would be embarrassing for you in a way that it wouldn't be for me."

His father took a few strides away from him, back toward the window, and a chance to think without having to face his son's scrutiny.

When the older man turned back around, he was the one that was now curious. "Where is this headed?"

"This?"

"Well, what would you call this-a stand-off, an impasse?"

"Perhaps it would be best to think of it as …a negotiation."

There was the tiniest of smirks on Richard Holmes' lips. "Then what is on offer?"

Mycroft had thought long and hard about what was feasible. He knew that this was perhaps the most important conversation of his life so far, and he wanted it to go right, for both his sake and Sherlock's. _Don't rush things. Let him come to it slowly._

"To start with, I want legal guardianship of Sherlock. I've drawn up the papers, all you have to do is sign and he is no longer your problem. You can be free of him, as you wanted to be, when you confined him at Kings Court. In exchange, I will withdraw the idea of court action. It's really just a formality- and it will be kept strictly private, confidential between the two of us."

The taller man nodded curtly. "And what else, because if that were all you wanted then we wouldn't be having this conversation except via lawyers. So, out with it."

Mycroft anticipated anger, but his father was being more subtle now. Probing and testing what actually was on the agenda.

"I sit my first year exams in two weeks' time, and then I'm free until October. I want to spend the summer at the estate with Sherlock, without you in residence."

Richard snorted in derision. "Why on earth would you want to do that? Leave the boy in an institution, for God's sake. You're supposed to be spending the summer on the internship at the House of Commons, or have you forgotten your promise to Sir Charles?"

"The machine of government will not grind to a halt because one intern fails to turn up. I've recommended one of the other boys on my course; he will suit Sir Charles' ambitions much better. I want Sherlock back in familiar surroundings with a face that he trusts. At the moment, that's me and no one else. He needs to get out of a place that assumes the worst of him."

"It's a waste of bloody time, Mycroft. He'll be a millstone around your neck. He'll drag you down, suck the life out of you. Instead of being…all that you could be, you'll waste energy trying to fix him. You're already compromising your own interests by turning down the internship; it's just the first step on that slippery slope. Don't do it. He's broken. Always was, always will be…a mistake. You think you're being noble and doing the right thing, but, believe me, you will regret this decision for the rest of your life."

Mycroft was unmoved and unmoveable. He waited, watching his father pace from the window to the side of the master's desk, and then back again.

"No, I can't let you do this. This isn't supposed to be how it turns out. You were all I ever wanted, all I hoped for in a son. You've never disappointed me. When I let her waste her life on Sherlock, she let me have you. That was the bargain we made."

"You didn't ask me for _my_ opinion about that idea, Father. I can't accept it. Since Mummy died, I've learned a lot about you, and not one bit of it makes me want to agree to your arrangement."

A hint of desperation crept into his father's eyes. "He'll break you the way that he broke your mother. Damn it, Mycroft- how can you do this to me? You're all I have left now!"

"No, father, you have another son, as I have a younger brother. And, unlike you, I am not able or willing to forget that."

Mycroft looked at his father, feeling as if a great chasm had opened up between them. He was seeing the human being there rather than his father, for the first time in his life. And he didn't like what he saw. The father he had always looked up to and respected was not there. In his place was a jealous needy man prepared to reject one son and to use guilt to coerce another one to go along with his plans.

He watched as the fire, the anger went out of his father's eyes, to be replaced by the toxic fallout of disappointment. The confrontation he'd been dreading for days was over. Odd, the explosion seemed to have blown out the flame of his own emotions; he looked coldly at the man in front of him and saw him for what he was- just a man.


	16. Chapter 16

**Periodic Tales**

**Chapter Sixteen **

**Caesium 133 **

_Caesium 133 is used in the most accurate atomic clocks. It serves as the primary standard for the SI definition of a second. This is based on the time interval taken to complete 9,192,631,770 atomic oscillations. The NPL CsFP2 caesium fountain clock in the UK is the world's most accurate measure of time. The atomic wrist watch was invented in 1949, and needs no winding. It keeps accurate time by being connected through radio waves to the atomic clock._

Sherlock was pacing in the mortuary. "Time of death, Molly; it's absolutely crucial." This was uttered in a growl. The detective was not in a good mood. He was tired, cold and hungry, running on nothing but adrenaline, coffee and nicotine patches for the past three days.

John watched him prowl like a caged animal. "Sherlock, ToD is never a simple mathematical equation. It's just too complicated- too many variables. If you push for an accuracy that is not possible, then you are putting Molly under intolerable pressure."

The long strides did not shorten. "Accuracy matters, John. Without it, we can't distinguish between the three suspects or, indeed, whether any of the three is a killer."

Molly Hopper tried to block out the noise of their discussion. She looked down at the slim figure of the teenager lying on the metal table. The photographs were done. The physical inspections, the temperature and rigor tests were over. She'd washed the body carefully, and the last red traces of dilute blood were now disappearing down the plughole at the end of the table. She slipped the shower head back into its clip, and stepped back to the body.

_Tell me who did this to you and when. Give us a clue._ Molly's professionalism when she was alone with a body did not stop her from thinking about the person who had once inhabited the dead body. This was Alice Craddock, aged fourteen and a school girl at the Henrietta Barnet School in north London. Her body had been discovered in the undergrowth of Victoria Park, Finchley Central, showing obvious signs of sexual assault as well as a single knife wound to the side of her neck. She would have bled to death in a matter of minutes, and been unconscious very quickly. The Metropolitan Police believed she had been killed elsewhere, because there was so little blood at the scene of the crime.

Alice Craddock was the third victim in as many days. Cheryl Miller, fifteen, had been found in Alexandra Park, Muswell Hill, and the first, Susan Chambers, in Waterlow Park in Highgate. All three within three miles of each other. All three had been killed the same way. The newspaper headlines were calling them the "the park princess murders".

The ME on site had taken the girl's liver temperature and estimated that she had been dead no more than two hours when her body was found by a dog walker. But, it was a cold afternoon, below freezing for once in London, and that could hasten the rate of cooling. Add to that the fact that she was naked inside a plastic bin bag, and time of death would be challenging to pin down.

Because Alice had been found so quickly after her death, the police had rounded up three possible suspects. One was a previously convicted criminal with a record of domestic violence, who was seen walking back from the park to his flat on Ballards Lane. The second was a teenager known to be doing drugs which he had bought on the other side of the park; he was high as a kite, and violent when arrested. The third was a dishwasher in a local Indian restaurant, who was late getting to work, and had not given his employer an excuse. He always walked to work across the park. Each one of the three men was big enough to have carried the slender teenager some distance in the black bin liner in which her body had been found. None of them had a watertight alibi for being in the area.

Earlier that afternoon, Sherlock listened into the interrogations of the three men, and plotted a time-line. In each case there was between ten and fifteen minutes of their time that was unaccounted for, where there was no corroborating witness to strengthen their alibis.

"I'm sorry Sherlock. I just can't be more specific. Time of death is between two and four pm- even that is dropping the usual contingency I put in when we don't know the actual place where she was killed. It might have been a lot warmer than where she was dumped, and we don't know how long she was there. It's the best I can do." The pathologist looked apologetic.

Without a word Sherlock turned and left the mortuary, slamming through the swing doors, leaving John to apologise for his abrupt departure. by the time John caught up to the brunet, he was halfway to Newgate Street where they hailed a cab. When John started to speak in the taxi, Sherlock just ignored him and sat with his eyes closed. Back at Baker Street, Sherlock lay on the couch with his eyes closed and his hands steepled. John fixed himself some soup, but the bowl he left on the coffee table for Sherlock went cold, untouched. The doctor sighed, watched crap telly for a while,and then switched over to the BBC a few minutes before the ten o'clock news. The usual programme intro counted down the seconds to ten pm.

Sherlock suddenly sat up and grabbed his phone.

"Lestrade, do you still have the suspects in custody?" The answer must have been yes, because Sherlock carried on, "Then find their personal affects handed over when they were taken in. Compare their watches. One of them has moved his by at least fifteen to twenty minutes. He's the killer. Come tell me when you've sorted it."

Lestrade showed up at Baker Street just before midnight. "You were right, Sherlock, although how the hell you figured it out, I don't know. There were three watches, and none of them was wholly accurate. The guy who worked at the Indian restaurant had one of those atomic watches- you know, supposed to be accurate as hell, but it was twenty minutes slow. Turned out to be a Chinese fake and he could alter the time on it. He swore he didn't know, but when we investigated the restaurant, we found the blood traces on a knife that he'd not had time to clean up. He killed her in the kitchen, then mopped the floor so no one knew, and took out her body in the bin bag to the park. When the cook showed up, the place looked clean as a whistle. When the dishwasher came back in, the cook just assumed he had just arrived and was late. So, case closed- all due to a watch."

John looked down at the consulting detective, still lying prone on the sofa. "Not bad for someone who doesn't even wear one." Sherlock smirked. "Don't need one, John. It interfers with my freedom."

oOo

Mycroft slid the leather strap into the buckle and tightened it around his brother's bony wrist. "It's special Sherlock, so don't lose it. You don't have to remember to wind it. The watch gets a radio signal from the atomic clock, so it's always accurate. So, no more excuses for being unpunctual. You can't pretend that the watch stopped or that it's slow. Because it's atomic it only loses a tenth of second every million years. Promise me that you will keep an eye on it, so you know what time it is."

Sherlock looked down at the clock face. "Atomic? How does that work?" His eyes were like saucers in wonder.

"Look it up yourself." Chemistry wasn't Mycroft's first love, not even his tenth when it came to academic subjects. But he knew his little brother's fascination was intense and he hoped that it would mean he'd take better care of this watch. And, more important, that he would use it to learn to keep to an agreed timetable.

They'd been home two weeks. At first, Sherlock was tentative around the house, as if afraid of the strange combination of both familiar and yet strange surroundings. For the first three days it was hard to get him to leave his room at all. Mycroft could understand the feeling, because it was odd for him, too. The house was the same, of course, and the staff, too- but with both Mummy and Father missing, it felt empty. The older boy kept expecting to hear his mother calling him, or to smell the scent of his father's cigarette smoke near the library or his office. For a ten year old who'd spent the last five and a half months confined to a hospital bed, the idea of having the freedom to roam the house must have been disconcerting.

Yesterday, Sherlock went missing. He didn't show up for dinner, and then Mycroft realised that no one had seen the boy since lunchtime. A frantic search with the housekeeper, Mrs Walters, yielded nothing. Mycroft and the gamekeeper, Frank Wallace, then tackled the grounds. With sixty acres of land to search, he knew it would be hard. Most of the staff working in the house and the farms went home by five, so there weren't many people he could rope into a thorough search. Calling them back, or worse, calling the local constabulary would be difficult to explain if Sherlock had just wandered off. He could just hear his Father's ridicule. "I told you Mycroft; he has to be institutionalised because he can't be trusted."

He tried to keep his anxiety under control. Mummy had believed that as a boy Mycroft needed the freedom to roam and had to learn the responsibility that came with it. Some might argue with that view in today's world of over-protective parents, but Mycroft had benefitted from it. She'd not allowed Sherlock that same freedom, because his autism made him more vulnerable. But Mycroft had played hide-and-seek with Sherlock since he was a toddler in the gardens closer to the house. When he'd deduced his brother's hiding place, he was often greeted with a smirking "Took you long enough." Every year, his brother became more and more adventurous and ingenious in his hiding places.

In Mummy's last summer, she didn't know that the nine year old had taken to sneaking out at night to explore on his own. Mycroft did not betray his secret, once he'd been sure that he wasn't at risk. He'd followed him a few nights just to be sure. "Just be sure to be back before sunrise, Sherlock; you know it will worry Mummy if she can't find you." But that was before Mummy died, before Sherlock's breakdown, before he ended up hospitalised for nearly six months- and before Mycroft had assumed responsibility for his brother's well-being. All those things now made it very hard for him not to feel every second of Sherlock's absence now as some kind of accusation of his own negligence.

Wallace had taken one of the estate's two Landrovers over to the far side of the paddocks and the farms. Mycroft was in the other one, driving through the woods and the pond. He'd learned to drive in this Landrover, and on a different occasion would have enjoyed the opportunity to do it again. Now, however, the windows were rolled down and he was getting hoarse from calling Sherlock's name.

Eventually, as the long sunlit evening turned to dusk, Mycroft spotted Sherlock beyond the deer park at the edge of the woods, sitting with his back up against a tree. He was sound asleep when Mycroft got to him, and clearly had not heard the vehicle or the calls. Relief warred with irritation. On the one hand, that fact that his brother felt able to explore on his own was reassuring; on the other, Mycroft was terrified that something might have happened to him while he was on his own. And to be gone for more than six hours was….too difficult to bear. For the first time in his life, he began to really understand why his mother was so protective of Sherlock.

Still, he held his own anger in check when he squatted down beside the sleeping boy. "Sherlock, wake up. Do you have any idea what time it is?"

The blue eyes that opened looked somewhat dazed for a few seconds, then took in the angle of the setting sun. "Oh, it must be…about 6.30? I don't know for sure; I haven't found my watch since we got back here."

"Sherlock, it's past nine o'clock. It's the longest day next week, when it won't be dark until after ten. You've been out of the house for six and a half hours. You've missed supper, not heard us when we were calling. You've scared the staff half to death."

That provoked a smirk. "But not you."

Mycroft decided that his relief outweighed his irritation, but his brother had to learn. He sighed. "No, I'm just _cross_ with you. If you want the freedom to roam, then you have to keep an eye on the time. I'll get you a watch tomorrow, if you promise you'll keep to our agreement. You show up for lunch and dinner and you tell either me, Mrs Walters or Wallace about where you are planning to go. Those are the rules and you will have to abide by them. Promise?"

The ten year old looked up at his brother and nodded.

"Ok, let's go home."


	17. Chapter 17

**Chapter Seventeen**

* * *

**Copper CU 29 **

_Copper __is an orange-red malleable metal with a high electrical and thermal conductivity, the second highest among pure metals at room temperature. In use for over 10,000 years, more than 95% of all copper used has been mined and smelted since 1900. The cultural role of copper has been important, particularly in currency. Romans in the 6th through 3rd centuries BC used copper lumps as money, but roughly half of all copper mined is used to manufacture electrical wire and cable conductors._

* * *

Mrs Walters came into the conservatory where Mycroft was reading. It was an overcast day in early July, with blustery showers, so he was trying to get a head start on his book list for next term. After the compulsory subjects in first year, he was now able to focus on just two of the three areas. He'd opted to continue with economics and politics, letting philosophy take a back seat. Next term, he'd be doing British Politics and Government Since 1900, Theory of Politics, and Macroeconomics. By dropping the Philosophy element, he could also squeeze in International Relations. So, he was now working through Raymond Aron's 700 page tome, _Peace and War: A Theory of International Relations_.

"Mrs Walters, you're hovering."

The Scottish woman shifted a little uncomfortably, even though the young man had not looked up.

When she didn't answer, he did so, and took in the uncertainty in her stance.

"I'm sorry to interrupt your reading, but your brother…"

Mycroft sighed. "What is it this time, Mrs Walters."

"I'm not sure I can explain it; you'd better look for yourself to see whether it is as dangerous as it appears to be."

Without another word, he put his book down and followed her down into the kitchen.

Sherlock had colonised the big wooden table in the middle of the kitchen, and there was a clutter of glass beakers, a hot plate, various bottles with clear liquids, the kitchen scale and, most oddly, an old broken lamp. The flex that led to the plug no longer had its plastic insulation and bare twisted wires had been cut into several lengths about an inch long. Some pieces were sitting in Mrs Walters' kitchen scales. There was a faint chemical whiff in the air.

"Sherlock, what are you doing?"

"Experiment."

"I can see that. The question was, obviously, _what_ experiment?"

"Metathesis, decomposition, displacement and oxidation-reduction reactions of copper."

Although to most people, those words would sound strange coming out of the mouth of a ten year old, Mycroft was never surprised by his younger brother's encyclopaedic knowledge.

Sherlock carried on, his enthusiasm making him rush his words. "It's _brilliant_. The copper is dissolved, then precipitated through various compound forms, and eventually becomes metal again- from pure copper to copper nitrate, copper hydroxide, copper oxide, and then copper sulphate before it becomes pure copper again. If I do it right, then the same weight of copper will be recovered at the end of the five reactions."

Mycroft's brow furrowed. "That sounds rather complicated. Where did you learn about this experiment?"

"I read about it in one of Father's books in the library. It's really very interesting, and I'm learning how the chemical formula changes, too. See?" He gestured to the detailed pencil drawings of the chemical formulae on a pad by the sink, for each of the chemical reactions. "Want to watch?"

Without waiting for their agreement, he switched the hotplate on, measured 10 ml from the beaker of clear liquid and put it into the beaker with the copper wire.

A horrible smell started to bubble up out of the liquid, along with a brown noxious looking vapour. The ten year old seemed utterly unfazed by the process going on in the beaker. He said over his shoulder, "You might want to turn on the extractor fan."

"Sherlock, is that an acid?"

"Yes- nitric acid."

"Where did you get it?" This was said with an edge of concern that Mycroft decided not to hide.

Sherlock looked up at his brother. "I made it yesterday. I got the gardener to let me have some of his ammonium nitrate fertiliser, and then I concentrated some of stuff he uses to clean the concrete in the stable yard, into hydrochloric acid ….. Why?"

Mrs Walters looked distressed. "Is it safe?"

The smell quickly dissipated, but an evil-looking brown vapour cloud seemed to hover over the surface of the now very blue liquid in the beaker. Sherlock switched off the hotplate and looked carefully at the beaker. "Have you got any ice, Mrs Walters? It will help cool it down faster so I can get on with the next bit."

Mycroft crossed his arms in front of his chest. He remembered his school days in the lab at Eton- and all the safety equipment that they had to use, from goggles and gloves, to fume hoods and hazardous waste disposal bins, not to mention the expert supervision from the chemistry master.

"Stop right there, Sherlock."

The tone of his voice made Sherlock look up at him in annoyance. "What now? The next part is a tricky bit. If I had a decent chemistry set, I'd have a magnetic stirring bar, but as it is I have to use a glass stirrer and keep it going like mad while I put the hydrochloric acid in drop by drop until the litmus paper turns blue- then I will have copper hydroxide."

"There won't be a 'next part', Sherlock, it's too dangerous to do here in the kitchen without the proper safety equipment- and you need someone who knows what they are doing to supervise you."

He watched his brother's face. First disbelief, then anger. Mycroft did not move or show any sign of being moved. When his brother broke eye contact, he was half way to a full blooded strop; Mycroft recognised the signs.

"Mummy used to let me do things with my chemistry kit. Why are _you_ being horrible?"

Mycroft sighed again. "Sherlock, when you did this sort of experiment last year, it was quite basic- I remember you using vinegar to take tarnish off pennies. But, this…strong acids, magnetic stirrers- chemical reactions that take precise measurements- you've outgrown the kiddie kit. You'll need proper equipment and someone who can teach you how to be careful."

"That's not fair! It's not my fault that I can do more now. I don't want to _play_ at this, or do boring stuff; it's too important"

"Sherlock…"

His brother just cut him off, shouting, "I'm not like you; I can't just sit in a corner and read all day. That's what they wanted me to do- keep quiet, stay out of trouble, I'm fed up with not being allowed to do anything- that's what they said, and you're just like them!" Before Mycroft could say anything, Sherlock stormed out the back door of the kitchen.

Mycroft's heart sank. He turned back to the table. "I'll clear up this …mess, Mrs Walters."

"Och, don't trouble yourself. I'll manage. And, I will be careful with the acids- get the gardener up to dispose of them safely." She looked down at the table. "I'm just sorry that he's so upset. He's right, you know, it doesn't seem fair after all the time he spent on his own at that clinic."

"I know, Mrs Walters; he's so _angry_ about it, and I don't blame him for that, but it's hard to know what's best."

On his way back to the conservatory, he decided that he would contact Dr Cohen and see what advice she might have to offer. Sherlock's temper was as volatile as the chemicals he wanted to work with. _Time to get a professional's opinion. _Things were not going to go "back to normal", even with the best will in the world. He picked up his book- _Peace and War_ seemed an apt description of his relationship with his brother at the moment.

oOo

The British Transport Police Officer was pacing to measure the distance between the electrified rail and the very dead body. The London Underground Manager was pacing too, but for a different reason. Although there was no tube station at Clapham Junction, both the Northern and District Lines tracks ran through the same area, and their trains had been stopped as well.

In the cold frosty morning, a Network Rail manager stood watching dispassionately, while DI Lestrade kept his eye on the two civilians standing on the platform about forty meters away. They were being held there by another British Transport Officer. Six of the seven men on the scene were wearing high visibility jackets, but one on the platform had refused.

"I know it's unusual, Mr Harker, but this civilian _is_ different and will help us get to the bottom of the problem. So, just bend the rules and let us get on with the investigation, please."

The Met had been called in when the third body in as many months had turned up on the tracks about near Clapham Junction. As the UK rail network's busiest junction, anything that stopped trains coming from Brighton to Victoria and to and from Waterloo and the West Country had to be dealt with urgently. The previous two deaths- both rail maintenance inspectors- had been put down as an unfortunate co-incidence of accidental deaths. The first man was electrocuted by coming into contact with the live rail of the London Underground tracks. The second one appeared to have been hit by a train, whilst inexplicably walking the track late at night back from the depot.

But, when this third inspector was also hit by a train, suspicions flared and the Met was called in.

Now faced with the fact that thousands of angry commuters were being re-routed through other stations until the Murder Investigation Unit could process the scene of crime, the Network Rail Manager was cold, needed a cup of coffee and, more important, his superior off his back about yet another delay to trains. It would be just his luck if his boss was actually on one of those trains stuck somewhere on a branch line in Putney. Harker decided that Health and Safety regulations could get stuffed.

He nodded, and Lestrade beckoned John and Sherlock onto the tracks.

Sherlock stalked over to the body; he didn't like being kept waiting, so made no effort to be civil to the Transport Officers or the Network Rail manager. He crouched down beside the body on one side, whilst John knelt on the other. The brunet examined the body, focusing on the hands and then searching the pockets.

"Lestrade, get someone to stand exactly where the other two bodies were found."

No please was added to leaven the abrupt command. _God, his social skills need work; must have a word with John about that._ Lestrade was used to it, but when people other than his own team were on a crime scene, such behaviour undermined his authority too much.

He grimaced and then said apologetically, "Sorry, lads, would you mind?" The two Transport officers grudgingly took up their positions, the first some fifty meters down the southbound fast line, the other tangentially across, almost a hundred yards away on the tracks that led to the depot for the trains that terminated at Clapham.

Sherlock stood up and watched them take their positions, then looked down at his phone screen. From where Lestrade was standing, he had no idea what Sherlock was looking at.

The Network Rail man looked equally suspicious. "What's he doing?" The two men watched as Sherlock turned slowly, making a complete 360 degree circle whilst scanning the horizon. He looked down at the phone again and then nodded as if to himself. John stood up and the two men came back to the others.

"You can move the body now, Lestrade, no need for forensics to process the scene. They won't find anything, and the case has been solved anyway." The brunet turned to the manager. "Once the body's moved you can put the power back on, although I suspect that you will find the signaling to let the trains out of the depot will not be working when you do."

Not one of the British Transport officers, the London Underground man or the Network Rail manager made a move.

Sherlock rolled his eyes and sighed. "Very well, let's just annoy every commuter in south London for a little while longer, shall we?"

Lestrade kept his temper. "Just get to it, will you, Sherlock?"

"Right- in the pocket of the dead man, I found this." He held out a metal object, about six inches in length.

Harker scowled. "That's a key component of a signaling device. Oh shit! That means he was trying to steal it when he got hit."

Sherlock rolled his eyes. "No, that is what you are _meant_ to think! There were no grease marks or dirt on his hands, which he would have if he had stolen this. So, no, this was planted in his pocket. This is the aftermath of cable theft gone bad, but not in the way you're thinking. The two previous bodies were found on the same trajectory – leading to that small building over there beside the train shed. Do tell us what's in there, Mr Harker."

The Network Rail manager looked over at the small building. "That's the supply store for the maintenance work we've been doing, part of the Clapham to Waterloo upgrade."

"And now tell us what will be on large wooden wheels in that shed?"

Harker looked startled. "Oh! Copper cable!"

Sherlock snorted. "At last, the penny drops. Yes, Mr Harker, you will find 100 percent pure copper strands that have an amazing value to recyclers who are more than happy to look the other way when organised crime brings them a regular supply of high grade metal."

The manager bristled. "We know that, of course we do. Cable theft costs the rail industry £16 million a year, and every time some tom, dick or harry comes along to nick one of the copper elements of the signal mechanism, it means that hours of commuter delay cost even more. With the price of copper soaring on world commodity markets, thefts from tracks have gone up fourfold in the past two years. But, that's why that store shed is protected by really secure locks and CCTV cameras."

Sherlock just shook his head. "Put yourself in the shoes of the criminal and choose- instead of trying to nick a short length of cable and bits from the tracks where stealing risks life and limb, why not go for it in mass quantity in a nice convenient shed? If you investigate, you won't find any prints or signs that the lock has been forced. Why? Because for them, this is the egg laid by the Copper Goose- an unending supply of copper in conveniently available form. Somebody who is authorised to use that shed is doing just that-oh and while he does his proper job, he also manages to steal the stuff. He's probably also cooked the books so cable going missing doesn't even show up. This is what organised crime does."

He looked down at the body. "This poor fellow probably saw something he shouldn't have, like the others, and paid the price. Easier to hide a body here in plain sight than almost anywhere else- all three had a legitimate reason to be on the tracks, all three could be first dismissed as accidental death if the bodies got hit by a train. And if you did get suspicious, just plant a bit like that in a pocket, and you all draw the wrong conclusion. Works every time, I am afraid." He gave the Network Rail manager one of his fake smiles.

The consulting detective now looked at the British Transport Police Officer. "Ignore the CCTV camera evidence; it's easy to subvert with a loop. Just put a new camera inside the shed, discretely, and I can guarantee that you'll find your thief. Better still, don't stop at the little guy who actually walks in, put a tracer on the cable and see where it shows up at a crooked recycling yard. They are supposed to be getting photo ID of anyone selling copper cable, and automatic number plate recognition might show you the cars being used to do it. Track it back to the top guys, and, who knows, you might net what the Staffordshire police did when they found £700,000 worth of copper in a single haul."

The consulting detective rubbed his gloved hands, his breath clouding in the frosty air. "Right, John, fancy a hot breakfast? I know a little café down Grant Street that serves a very good full English."

Harker looked at the Met DI as Sherlock walked off back up the line to the platform. "Who is that guy, Lestrade?"

Greg just smiled. "Just someone I know who has been rather helpful in the past. Now, can I suggest we follow his example, and get off the tracks so all those commuters can get into work?"


	18. Chapter 18

**Chapter Eighteen**

_Copper, when exposed to air, often forms a green carbonate layer called verdigris. It does not react with water, but it slowly reacts with atmospheric oxygen forming first a layer of brown-black copper oxide (tarnish). Over time, this turns green as it combines with sulfur compounds in the air. This layer stops the further, bulk corrosion, giving the copper an impenetrable layer of protection. _

* * *

"Can I get you some more soup, Doctor Cohen?" Mrs Walters dipped her ladle into the tureen, and when the dark haired young woman nodded, she put another portion of the mushroom soup into her bowl. When Mycroft nodded as well, she served him seconds, as well.

"This is a soup to die for, Mrs. Walters; really, you must give your cook my compliments. I haven't had home-made soup for …must be months."

The Scottish woman beamed. "Well, I'll thank you for the compliment, because Cook's on her annual holiday and I'm the one wielding the knife in the kitchen this week. It's just a simple supper tonight, I'm afraid, doctor, but tomorrow I'll do better. I am sure that you're too busy at the hospital to look after yourself properly, so let me spoil you for a while."

Esther Cohen smiled, but then looked thoughtful. "Actually, Mrs Walters, you must call me Esther. You, too, Mycroft. If Sherlock is ever going to accept me, then we've got to get him thinking of me as something other than yet another beastly doctor."

"Of course, my dear. I understand perfectly. I will pass that on to the rest of the staff. Now I'll be off to the kitchen to see what's happening to my fish."

Esther watched the kindly woman leave, and then smiled at Mycroft. In a whisper, "She's like something out of a film. In fact, this whole place is. When you invited me down, I had no idea that this is where you lived."

The psychiatrist had arrived only an hour ago, tired and hungry after her last thirty six hour hospital shift. She'd accepted his invitation readily. "Really, I had already booked the the next four days off to finish an article that I've been promising a journal for months. Once you telephoned, I actually had a reason to stop procrastinating, and finished it all but the references and a few tables. I can do that while I'm with you."

"Are you certain that you want to take on a private patient?" Mycroft was trying to be diplomatic. If the young doctor was too busy with her hospital work and research, then he needed to know now; if she was, then the visit would be needed to pick her brain about a suitable therapist. He had come to trust her judgement over the past three months.

She gave him a reassuring smile. "Normally, someone in my position wouldn't be seeking a private patient. I'm at least three years away from wanting to set up my own practice. But, I meant what I said when I spoke to you on the phone. If there is any way I can help, then I will. Sherlock is a special case. You've been through enough to get this far. So, if – and I do mean if- he is willing to engage, then, yes, I will do what I can."

She had grown to respect Mycroft. When he'd first sought her help at Oxford, she had been impressed with his mature attitude and manners. The time since must have been horrible for him. Still having to deal with his own grief over his mother's death, he had been determined enough to do what was needed to rescue Sherlock from the clinic, even if it had cost him his relationship with his father. To abandon him now would be too cruel. She just hoped that she'd be able to reach Sherlock. Based on what she had seen at the Mount Sinai centre, she wasn't sure.

The two of them agreed that if Sherlock was to accept her therapy, he would need to meet her on familiar territory, and in a way that did not awaken the distrust that he'd shown to anyone in a white coat. "I only saw him twice at my uncle's facility during the two weeks he was there. Unfortunately, I was on a beastly shift cycle then; new joiners tend to get the worst assignments. The first time, he ignored me completely, the second he was sound asleep. So, hopefully I have not made him too distrustful."

Over the light supper, the two of them talked. "You said on the phone that his mood has been volatile. Could you explain more?" She took the opportunity to return to her soup.

Mycroft put his spoon down for a moment, to butter his roll. "He wouldn't budge out of his room for the first three days. It took nearly a week before I could talk him into getting dressed. He spent two whole days in the Library, totally engrossed in Father's chemistry books. He then sort of. ..reclaimed the house. Spent time just wandering about, looking at things, picking up things. It's as if he'd forgotten them, and wanted to re-familiarise himself."

"That's normal. One of the side-effects of ECT is memory loss. So, a little uncertainty is to be expected. And when a child has been institutionalised for months, they can get fearful of being suddenly able to have all the freedom that comes with being at home." She took a bite from the warm bread roll. _God's above; she even does her own baking._ It was heavenly. Ever since starting at the Royal Bethlem Hospital, she'd been living on a diet of frozen meals.

The young man across the table had impeccable manners. She watched as he filled his soup spoon again the old-fashioned way, by dipping it away from himself. It was a simple act, but one in keeping with the aristocratic background. What might look like an affectation in someone else just looked natural with him.

"Well, he soon took advantage of that freedom. Last week, he disappeared for six and half hours, and I finally found him at the far side of the estate, almost four miles from the house. On the one hand, I was glad to see that he felt confident enough to roam at will..."

Esther completed the sentence for him. "…and on the other, it must have been worrying that he was unsupervised for so long a time." She had a lot of sympathy for the young man, thrust into a parental role like this. _So difficult; he's scarcely more than a child himself._

But the object of her scrutiny responded quietly, in an adult manner with polished poise. "That was not the problem that led me to contact you, Doctor." She frowned at his use of the title. "…Esther; no, it was when I had to stop him from a rather hazardous chemistry experiment that he was doing in the kitchen. Sherlock lost his temper, started shouting and came close to a melt-down. I haven't seen one of those for at least two years. Then he stopped talking to me, or to anyone, and retreated to bed. He could always sulk for Britain, but this is different. This isn't a sulk; I think it might be more serious, perhaps depression. It's been three days. He won't talk, won't eat, won't take his pills. It's like he's gone back to square one, where he was almost a month ago. And because he's not taking the medication you prescribed …well, I just didn't know what to do."

She looked thoughtful at his description. "You need to understand something about what happens to a child when they are in hospital for such an extended period. They form a sort of shell- an impervious layer. It's a bit like silver, brass or copper- you know, the longer it goes uncleaned, the dirtier and more tarnished? Well, being in bed all day, drugged, without stimulation or the comfort of friends and family- it's a bit like that. The longer they are in, the heavier the tarnish that has to be cleaned off. What you see of them in a hospital is only the faintest hint of the shine that should be there- and that only happens if the patient isn't scared. It's safer under that protective layer. What happened with Sherlock this week sounds like he's just decided to hide behind that protection again. Have you told him about me being here?"

"No, but he will know. My brother, even when he is shutting himself down like this, is amazingly perceptive. My mother told me that doctors never understand him. They assume he has a sub-normal intelligence, because he won't communicate. My father believes them. Mother knew better, and so do I. He's amazingly bright, just… not normal. I wish I knew what went on his head, how to reach him. As he's grown up, he's learned how to hide the anxiety. But I think it's still there. Mother found a way to keep him focused on things, and when he focuses, he is amazing. That experiment, for example, the one I stopped him from doing, was something out my father's first year university text book. With the right equipment and supervision, I have no doubt that he'd have done it perfectly."

He looked down at his empty bowl. As if she had seen his last spoonful, Mrs Walters arrived and whisked the bowls away to the side-board. She set warm plates in front of them. She returned with a silver dish, laden with freshly grilled Dover sole fillets. Esther used the silver fish servers she was handed to take one onto her plate. Once Mycroft had been served, the Scottish woman re-appeared at Esther's shoulder with a dish of new potatoes in parsley and butter. The aroma reminded her of how hungry she was.

Once the food had been served, Mycroft asked her if she would like a glass of wine.

"Only if you join me."

He nodded, and Mrs Walters brought a bottle of Pouilly-Fumé Baron de'L to the table, pouring them each a glass before returning it to the ice bucket. Esther spotted the vintage and was impressed. _I could get used to this. _

To stop the daydream, she returned to what they'd been discussing before Mrs Walters arrived. "What you've just described- a bright highly intelligent young boy -sounds more like an Aspergers, a high functioning autistic. It seems miles away from the locked-in Sherlock I saw at Mount Sinai. Being deprived of books, of stimulation for so long would have been very hard on him."

"I think that's what surprises me about the whole thing. The Sherlock I know would never have been content to just sit there. Until last summer, he still threw tantrums like a four year old. And his biggest complaint? He hated, absolutely abhorred being _bored_. When I finished at Eton I spent most of last summer abroad with relatives, but the time I was here, I could see how much improvement there was. Instead of talking at me, we had the first real conversations ever. He was fascinated with chemistry and incredibly advanced. It was like no one had told him that nine year old couldn't do complicated formulas. But, by November I knew mother was dying. When I got home at Christmas, he knew something was dreadfully wrong, too. However horrible it has been for me, it's been far worse for him. Without her, I fear he has lost his way utterly."

"Well, don't despair, Mycroft. I hope to find a way to re-connect, starting tomorrow." She picked up her fish knife and fork and started in on the fish.

The next morning after breakfast, she went up with Mycroft to Sherlock's room. It wasn't where she expected. Unlike the other main bedrooms, Sherlock's was not off the main upstairs corridor. She had slept in an amazing room on that floor, with a four poster bed, and a pair of mullioned windows overlooking the garden. Instead, Mycroft led her down one of the wings and then up another flight of stairs. He explained as he went, "as children we both started in the nursery up in the east wing- a small bedroom, with an adjoining door into the nanny's room, and shared bathroom facilities. There's a playroom too, so we could be noisy children without disturbing the rest of the house. Sherlock just preferred it up there, and even when he was able to fend for himself and the nanny left, he refused to take the room that you slept in last night."

Mrs Wallace came out of a room carrying a tray- she shook her head, looking down at the untouched meal, before heading off down the stairs.

"Mycroft, I need to try to talk to him on my own. I don't mind you listening in from out here, but I'd rather you weren't in there. Might make him say what he thought you wanted him to say."

Mycroft laughed softly. "You don't know my brother, Esther. That's the last thing he would do." As she pushed open the door, he found himself wishing her luck. They all needed it, badly.

oOo

"Smashed, you say? Copper doesn't often 'break'- it bends, so what exactly did you find?"

Susan Chambers ran the Morse Fortescue gallery on the Kings Road. Her tale was piquing Sherlock's curiosity.

"Well, we specialise in small bronze pieces. Bronze is usually 88% copper and 12% tin, but this was special- pure copper, that had been treated to have that lovely green finish from the very start- makes it look old even when it isn't. The workmanship is superb. There were six in the set made by the Italian artist, Beppo Goldini. He used to work out of a studio in Hoxteth, but he's been gone for nearly nine monthes- said to have retreated to the hills of Calabria to do his next series. Very _avant garde_, very collectible, his pieces- incredible prices. They are abstract, but suggestive of animal forms. I've sold three, two more of the six are out on loan at corporate offices, and I've just got the one left in the shop. Or, rather, I did until I came in this morning and found it smashed. Flattened- looks like someone took a mallet to it and just bashed it flat until it looks like …a squashed piece of metal junk."

The Art Gallery owner was clearly distressed. "The Met's Art and Antiques Squad just called it vandalism- nothing was actually stolen, so they aren't interested. Didn't even send a detective, just a constable, who went through the motions, dusted for fingerprints and all, but said there was no evidence of a break-in, and asked if I thought any of the staff might have a grudge against the artist or me."

"And do they?"

She looked annoyed. "Of course not, Mr Holmes; I don't' know why someone would do it, but that's why I am here asking you to look into it. And it's not like this is the first time."

That raised a consulting detective's eyebrow. "Explain."

"Well, I contacted Beppo by e mail and told him about it; to be honest, I wanted to know if I could get a replacement. He replied that day before yesterday he'd been contacted by the Barnicot Bank offices to say that the two figures they had on display had been stolen. When the police investigated, they found the shattered pieces of the figures which were found in the courtyard of the bank the next morning. The bank called Beppo, wanting to know if he could fix them. He said, maybe in a couple of months' time, when he is back from Calabria."

"So, three statues in as many days. Does he have any idea who would want to do such a thing?"

"No. He is as perplexed as I am. I can claim on the shop insurance, and so can the Bank, but that's not the point. It's that fact that someone is going around smashing up beautiful pieces of art, and no one seems able to stop them. Will you help me find out who is doing this?"

Sherlock nodded. "Leave it with me. I will not be able to do anything today or tonight; I have a commitment to be at New Scotland Yard this afternoon on another matter, but can pick this up in the morning."

She looked relieved. "Thank you, Mr Holmes, for taking this seriously."

When John came down the next morning to fix himself a cup of tea, he saw Sherlock's phone buzzing on the kitchen table. He called down the hallway to his flatmate, who was in the bathroom- "Sherlock- looks like you've got a text from Lestrade."

Sherlock popped his head out of the bathroom door, and John could see that he was in his pyjamas and blue dressing gown, with half of his chin was still covered in shaving foam. He brandished a razor, "Just read it to me, will you- my hands are a little busy at the moment."

"**8.12am Come instantly, 131 Pitt St Kensington GL**"

In less than three minutes, Sherlock emerged freshly shaved, buttoning up his shirt. "Coming, John?"

"Yes, but I need coffee if I'm going to miss breakfast. While you finish getting dressed, I'll get two takeaway coffees from Speedies. Meet you outside. If you get there first, try to flag a cab, but please, this time, _wait_ for me."

It was a sore point. The last time he'd done this, Sherlock had been so focused on the case that he hailed a taxi, jumped in and left John to come running out of the café with the coffees. It cost twice as much as it should have to get the two of them to the crime scene and left John in a seriously grumpy mood for half the day.

Luckily, there was no queue at the café, and he emerged carrying the two hot coffees just as the front door of 221b banged shut behind Sherlock. The taxi to a backwater of Kensington was spent in silence as they both enjoyed the caffeine and the spectator sport of watching a cabbie pit his knowledge against the volume of London rush hour traffic. Thirty five minutes later, the taxi pulled up at the police tape at the end of Pitt Street, a side road between Kensington Palace and Holland Park. Sherlock hopped out and lifted the tape, walking to the front of white fronted terraced house at Number 131. The door was answered by a constable, who gestured them into the hall. "Lestrade is in the drawing room with Horace Harker, who's pretty shaken."

Sherlock went into the light filled living room that looked out onto the back garden. An exceedingly unkempt and agitated elderly man, clad in a flannel dressing gown, was pacing up and down in the room, while Lestrade was listening to his tale with a look of considerable scepticism on his face. "I'm a newspaper editor for God's sake, and when I find myself right smack in the middle of a murder, I can't seem to put two sentences together that make sense."

Lestrade introduced Sherlock and John, but learning who they were only seemed to rile the editor even more. "Of course, I've heard of you. You're the Boffin and he's the Bachelor." John just put his hand over his eyes in dismay. "Please tell me you aren't the editor of THAT tabloid."

That was the first time the older man smiled. "No, of course not. I'm the editor of a broadsheet quality paper; but I've still heard of you two. Just solve the case will you, and I'll give you a chance to put the record straight."

Sherlock had been ignoring the conversation, instead pacing about the room looking at the modern furniture, the art on the walls. He stopped and asked Harker, "You've lost a small piece of art that went right there." He gestured to a conspicuously empty space on the display shelves beside the fireplace. "And it was a bronze piece by Goldini, wasn't it?"

"Yes, how did you know?"

"That's not the reason I brought you here, Sherlock."

"No, of course not, Lestrade, if you're on the case instead of the Met's A&A squad, then someone got murdered last night- probably has something to do with the theft, however."

"We haven't proven anything yet. The body has already been removed to the morgue."

The editor was still in a state. "I practically fell over it last night, when I came down to investigate a noise. I saw the French door was ajar, went out onto the patio, to find a man with his throat slashed open and a knife lying in the pool of blood. Christ, it was like something out of a bad American cop show."

Lestrade now took over. "He was a tall man, tanned and physically fit. Casually dressed, but no ID on him. There's a phone, but we've not found much on it- one phone call made last night- we're still trying to trace the mobile number it went to, and a photo." Lestrade still had his gloves on, so he took the phone out of the evidence bag and showed it to Sherlock and John. The photo was of a man, shot in bright sunlight, against what looked to be a Mediterranean seascape.

Sherlock smiled. "That's interesting."

"What!" Lestrade realised that Sherlock recognised the man in the photo.

"More like 'who', Lestrade. That's Beppo Goldini, the artist."

Horace Harker looked startled. "Let me see that. I never met the guy, just got the piece from a gallery on the Kings Road." Lestrade showed it to him, just as his airwave radio crackled into life.

"Got some broken bits of metal here, Gov. Think you might want to take a look."

It was seven doors down, in the front garden. Two pieces of twisted metal, a soft green on the outside, but shiny copper from the inside. Sherlock put on latex gloves and handled the piece. A smirk formed in the corner of his mouth. "Interesting, John. The pieces are hollow."

He was on his phone within seconds. "Miss Chambers. I need you to text me with the names and addresses of the other two owners of the Goldini pieces. Yes, you can forget about the one you sold to Horace Harker; I'm there now and it was given the same treatment as yours and the two at the bank. Can you recover those two for me, please, and keep them with yours, for the time being. I will need you to bring them to Baker Street tomorrow morning."

From the confident tone of the call, John realised that Sherlock was well on the way to solving the case. "Care to let me in on the secret, Sherlock?"

"All in good time, John. First, though, I need you to do me a favour. You need to go to the Hoxteth studio and find out who is in the rest of the building. I think you will find that it houses businesses other than artists. Lestrade, you're going to run an Interpol ID search for the body found last night. Odds are he's an assassin, sent to kill Beppo Goldini."

The DI shook his head. "Then he's about 800 miles too far north. According to the Italian authorities, Goldini is in Polistena; that's in Calabria, I'm told. He has a studio there."

Sherlock was smiling at his phone. "As you say, Lestrade. However, if you will meet me tonight at 8pm at this address in Chiswick, I shall happily prove you wrong."

And so he did. The DI and a constable watched from inside the house in Chiswick, and Sherlock and John from the back garden's shed, as a black clad figure broke into the house and emerged only a moment later carrying a small statue. On the pavement stones, he took a chisel out of his pocket and proceeded to gently tap at it. There was a groan of despair and then he pulled a mallet out. Laying the statue on the ground, he proceeded to smash it to pieces.

Sherlock whistled, and the constable sprang into action. Caught in the bright security light that came on, the figure dropped the mallet and sprinted to the garden fence. John was quicker. Caught his legs and hauled him back onto the grass. Lestrade pulled the man's balaclava off and shone a torch onto his face- it was Beppo Goldini.

The DI was amazed. "But, why? Sherlock, I don't get it, why on earth would an artist go around smashing up his own art work? It makes no sense!"

"It makes perfect sense, and if you join us tomorrow morning at Baker Street at ten o'clock in the morning, I will show you why."

The next morning John poured coffee for Lestrade and Miss Chambers. Then to John's surprise, Mycroft came up the stairs carrying a box. He gave his brother a smile, and the box. "As requested, collected from the owner in Bristol."

There on the dining room table were five piles of smashed, twisted and broken metal. Sherlock opened the box and unwrapped a sixth perfect statue. He retreated to the kitchen, "Pour yourself a coffee, Mycroft, shan't be a moment." The doctor didn't go much for modern art, but this was special, and as he sipped his coffee the four of them stood around the table, admired its strange textures, swirls and almost muscular shapes, all softened by a deep patina of green.

Sherlock came out of the kitchen wearing goggles, carrying a large glass bowl and a glass bottle with a pump spray fitting on the top. He placed the figurine in the bowl and pulled on a pair of heavy-duty rubber gloves. "Stand back, this is a weak solution of nitric acid, but it will react. You might want to open the window John; it can be a bit smelly." He started to spray the copper artwork. Within seconds a horrible smelling brown vapour began to steam off the copper, and blue liquid began to accumulate in the bottom of the bowl. Then he grunted, and stopped spraying, pulling off his goggles in triumph. "There it is."

He picked up a pair of tweezers and carefully removed a small piece of dark metal that had been embedded in the statue, hidden under the green.

He held up the sliver in the tweezers, for the others to see. "This is a very interesting item- a tantalum capacitor, built around a new ceramic foil. Very hush, hush. Stolen from the same building of Goldini's London studio. Mycroft, once the acid has been dried off, you can return it to its proper owner."

"Thank you, Sherlock. We have improved the surveillance and security at the design sub-contractor, so it shouldn't happen again."

Miss Chambers was looking really confused. "Mr Holmes, I really don't understand."

"It's basic chemistry. Take one artist who has a studio in the same building as a defence contract design company, add greed and an interested party in the shape of the Camorra – that's what the mafia are called in Calabria by the way- then introduce a catalyst, probably Chinese, who want to lay hands on the latest piece of military aircraft avionics, and you get this case."

"Interrogation will probably get him to confess to the thefts, Lestrade, and to the murder. He was lucky to kill an assassin. I'm sure he'll confess if you threaten to let him go. Whether a Camorra cutthroat or a Chinese agent got to him first would be an interesting wager to make, if I were a betting man. Goldini must have stolen the capacitor, and then realised that he needed a safe place to put it. He carved a niche in one of the six statues he was making, inserted the sliver and then finished with the process of creating the copper carbonate finish- verdigris to you. That hid it well, so he went back to Calabria to negotiate a price with the Camora. Took a while to agree- possible because they held an auction to ensure they got the highest bid."

He smirked. "Mycroft by the look on your face, it must have been higher than what the British could afford to get it back."

The elder Holmes looked down at his umbrella. "I couldn't possibly comment on such wild speculations, brother."

Sherlock continued. "Goldini comes back to recover the chip to discover that he's forgotten which of the six he put it into. He thought it was in one of the two at the Barnicot Bank, but when he burgled them, found he was wrong. So, he started recovering them one by one, trying to find the capacitor. He covered his tracks by making it look like vandalism."

"Basic chemistry, as I said; you can hide all sorts of things under a layer of verdigris. It provides a shield, protecting the metal underneath from corrosion." He looked over at the gleaming red metal figure. "I rather like it better in the pure copper state, but if the owner wants me to put the green back on, I'm sure I could oblige."

Mycroft stood up. "No need, Sherlock. I bought it off the collector, rather than have to explain why we wanted it back. It's yours. Consider it a souvenir, a token of my appreciation for your help."


	19. Chapter 19

**Author's note**: Another combination of flashback combined with a hefty dose of case fiction, which is another adaptation of an ACD canon story. I won't apologise for the length. Some stories need it, but that's the reason for posting every other day…

* * *

**Chapter Nineteen**

_Copper is a transition metal on the periodic table, derived from __Latin _cuprum_, meaning '__from the isle of Cyprus', which is famed for its copper mines. __Romans in the 6th through 3rd centuries BC used copper lumps as money.__ In the US pennies are made from 97.5% zinc, coated with 2.4% copper; in the 1950s it was the other way around- 95% copper, 4% tin and 1% zinc. In the UK, pennies are steel, coated in copper since 1992. This makes them thicker than the old pennies, and magnetic. _

* * *

Esther walked into Sherlock's bedroom and pulled the chair from the work table under the window. She put it beside the bed and sat down, whilst looking at the tangled mass of sheet and duvet. Presumably, in there somewhere was a ten year old boy attempting to ignore her. She pulled out a well-worn book from her bag and opened it to a place where there were several loose sheets.

There was no sign of life under the bedclothes, no acknowledgement of her presence. Of course, he knew she was there, but if he wanted to pretend she wasn't, then she had to find a way to make him come to her, rather than the other way around.

"Sherlock. What's the chemical symbol for copper and where is it on the periodic table?"

She didn't expect an answer. But, it should start him thinking. She consulted the handwritten grids, and their dates. "It's important whether you know the answer or not. In March, you did. Then in April, you still knew it. But in early May, you'd forgotten it. And you still couldn't remember it in mid-May. So, I have to ask you now- letters and numbers for copper. Any idea?"

There was a slight movement on the bed, then a disembodied voice.

"Cu, 29, atomic weight 63.546. A transitional metal in the D block on the table. Twenty nine isotopes- that's a coincidence, nothing to do with its periodic table number. No allotropes."

She smiled. A few dark curls from a tousled head edged out from under the blankets at the wrong end of the bed- near the footboard rather than the headboard, "Why do you want to know?"

"Because it matters if you've remembered it, or whether you re-learned it since you got back home."

For a moment, nothing. Then the bundle of sheets moved, and the boy sat up.

"WHY? Does it matter?"

No eye contact, he was looking down the far end of the room rather than at her. Following his line of sight, she smiled. He was looking at her, in a way- her reflection in the full length mirror that was on the back of the door she'd used to come into the room. She looked back at him rather than the mirror, so they wouldn't have direct eye contact.

"Do you know why you were forgetting it, when you were in the clinic?"

A shadow seemed to chase across his face. "They wanted me to be stupid. The pills, the mask. They were making me stupid, making me forget things."

"Which is why you starting testing yourself, using the table." She held up the sheets and the book, so he could read the title in the mirror. Even with the letters appearing backwards in the reflection, he recognised it, and turned to her.

"Oh, that's MY book!"

She handed it over to him. "Why's it important?"

In a matter of fact tone, Sherlock just said "Mummy gave it to me; a birthday present. It's all I had to read."

"Why didn't you ask for another book?"

"They just had _children's_ books; boring. The others on the ward- they just wanted to _play_ with toys and read _boring_ books." His distain was clear. "This was the only good book there, so I read it."

_Now I need to know just how clever he is._ "If you read it over and over again, you must know it by heart. Can you remember what's on page 200? Don't peek."

He was surprised by the question but thought about it for a while. "256 pages, including the index. Metals- definitely. Not Gold, silver or copper; the book does those together first. Then tin and lead. Must be mercury." He opened the book, turned to page 200 and smiled.

_He likes being right. Either eidetic or close to it. It must have been terrifying to find things…missing. _

"You're not stupid, but you let them think you were. Why?"

He looked away from the book, but didn't glance at the mirror. His hands were gripping the hard-backed covers tightly. _This bothers him; it upsets him that others think that of him. So, more socially aware than he might let on._

"Father thinks I'm stupid. He tells me that; I think he told them, too. I don't care what they think."

_Ouch. It won't hurt if you deny that it does. Protective barriers, indeed. _"Your brother doesn't think you're stupid."

"My brother doesn't think of me much at all."

_Ouch, again. I hope Mycroft isn't out there hearing this._

"He's the one who found you. It took him a long time, because you were very well hidden. He asked me to help find you."

Sherlock looked down at his book. "He's already counting the days until he goes back to university. He's always leaving. First, prep school, then Eton, now Oxford. When he's done with that, he'll get a job and leave again. That's the way he is."

The boy's voice was unemotional, but after he finished, Esther could see that he was now becoming disturbed. "Why does that upset you?"

"Because when he goes, Father will come back, and then there won't be anyone here but him and me. He _hates_ me."

Esther resisted the temptation to try to argue with the boy or try to tell him that a parent, even a distant one, wouldn't abandon his own son. She had not met Richard Holmes, and only seen him through the eyes of his elder son. And it was possible that Sherlock was right.

Since emotional development and empathy was a key diagnostic of autism, she had to probe.

"What does it mean to you- do you _hate _anything or anyone?"

He thought about it a moment, then said in a flat tone. "To hate – abhor, loathe, detest, abominate. It means to feel intense dislike."

"That's what a dictionary says. Do _you_ hate anything or anyone?"

The boy considered. "Mummy says,... no…she _said, _I have to use past tense… that I hate spinach because I can't bear the texture or the taste. I don't like it, and given a chance, I spit it out if someone forces me to eat it."

Esther smiled. _He's dodging this; he knows exactly what I mean. _ "Try again, Sherlock. You know what I am asking."

He frowned. "I don't KNOW what it means, do I? I just know that sometimes I get scared and then my hands start doing things they're not supposed to. I don't like that, so I try to avoid what does that to me, and that makes me even more anxious. Is that 'hate'?"

"Maybe. What makes that happen for you?"

"When I go somewhere new and there are too many people, too many faces I don't know, too much to see, hear, smell- it just scares me. Fight or flight, that's what Mummy called it. Made me try to stay, but that just ends up with me doing something wrong. That's why it happens a lot when Father is near. I get too upset; can't control things."

Unconsciously, the boy was picking at the edge of one of pages of his book, crumpling it between his fingers.

"Why do you think your father hates you?"

"Because he thinks I'm stupid. He thinks I should be sent away. He always said that. And now he thinks I killed Mummy."

Her heart sank. For a vulnerable child to lose one parent was devastating. The idea that he'd been rejected by the surviving one was even worse. But to think that he was being held responsible for the death of the one person with whom he had formed an attachment, well, it was hard to contemplate.

"Why do you think that?"

"Because he told me. We were in the car on the day after Mycroft left. He said Mummy was dead, and that I'd taken the best years of her life away from her, made her sick and she died. Now that she was dead, he would finally do what he'd always wanted to do, which was send me away." It was said in a monotone. No anger, no distress.

"Did you argue with him? Tell him he was wrong?"

Sherlock looked over at her in surprise. "Why would I do that?"

"Because your mother died of cancer, Sherlock, not because of you or anything she did with you."

"It doesn't matter. He hates me, he always has, and now he has even more reason to hate me. When Mycroft leaves again, Father will come back and then send me away to that place again. Only this time, he'll get the doctors to do something that means I forget everything. And not even Mycroft will be able to find me. He's got his own life to live; that's what Father says, and I must not bother him."

"How does that make you feel about Mycroft?"

Now he looked confused. "What do you mean?"

"Do you hate Mycroft?"

"No. He's right to leave. He's perfect and I'm not. Why would he care what happens to me when he isn't here?"

She could hear an undercurrent of anxiety in the tone of voice, and realised she had to act fast if she wasn't going to lose his attention. But before she could react, Sherlock shut the book and stuck it under his pillow. "I don't want to talk anymore. My stomach hurts."

"That's probably because there is nothing in it, Sherlock; you should have eaten Mrs Walters' breakfast. I did and it was delicious. Before I go down to enjoy some of her coffee and pastries, I'm going to leave you with a present." She put three pennies down on his pillow. One of them was brand new, gleaming and shiny. The second one was a very dark brown, the third green. "Tell me the difference."

Sherlock looked at them and his brow furrowed in concentration. "That one's new." He put his head down close to the shiny penny, focusing on it carefully. "No, not just _new. _Give me the magnifying glass on the table behind you." Bemused, she did as ordered. He examined the shiny penny. "It's in _mint_ condition; hardly been exposed to air. Where did you get it?" This was delivered in a voice slightly higher pitched with excitement.

"The Royal Mint. Brand new- took it out of the plastic package about fifteen minutes ago."

He was on his elbows now, using the glass to look at the other two on the pillow. "The dull brown one's got a layer of copper oxide.….with a few faint traces of copper sulphide- that's green. Happens when copper is exposed to air; think of it as burning, just really, _really_ slowly. The brown penny has both in the tarnish layer but it's been in people's hands and pockets, so the green suflide gets knocked off; it's a powder." He moved onto the third penny, the green one. "This penny- it's been in the sea, I think. That means it first formed cuprous chloride, with the sea salt, then cuprous oxide and cupric hydroxide, before turning this colour green, which is malachite- that's CuCO3 CU(OH). That takes a _long_ time. Given the state it's in, this one is old- not just plated, but ninety five per cent or more copper, so it's old, really old."

She smiled. His attention had shifted away from thinking about his family and his time in the clinic. She set him a challenge. "The corrosion is so bad that I can't read the date. Think you can clean it up enough?"

Almost instantly, his mood brightened. "Of course." He looked at it closely again with the magnifying glass. "Can't read the writing, but it's a King's head, not a Queen, so before 1952. People don't want these to be too clean; hurts the re-sale value if it looks like new. So, I will have to use a dilute acid. Maybe citric-based or vinegar, not sure which to start with."

"Would you like me to bring up one of the books in the library to help you study them more?"

He thought about her offer. "You won't know the right one, so I'd better get it myself."

"You will need to wash and get dressed properly, if you are planning to spend time in the library."

He was already out of the sheets, and she watched the ten year old streak to the bathroom, totally unselfconscious about his own nakedness. She smiled. _The chemistry works. We can do this._

oOo

"An overnight trip to Cambridge? To stay at your old college? Yeah, I think I can fit that into my diary." If John was surprised at Sherlock's request, he hid it well enough not to arouse his flatmate's suspicions. The chance to get to know more about Sherlock's earlier years was too good to pass up. The man was incredibly reticent about his past, and John's natural curiosity meant he was more than happy to accompany him.

On the train up from Liverpool Street to Cambridge, Sherlock explained. "The Master of my old college called last night, asking for my help on a case. At first, I was inclined to say no, especially when he told me it involved the theft of some papers from his office. More cause to get the police in. But, he made a case that this was not an ordinary theft; it risked exposing not just the college but also the University itself to a significant scandal, and that every attempt had to be made to keep it absolutely quiet."

"How long do you think it will take?"

"Can't say until I know more about the particulars, but he said if the theft wasn't solved by midday tomorrow, then it will become public, so we have a tight schedule. He offered us a night's college accommodation and dinner at High Table tonight. If you can be bothered with that sort of thing, Trinity's wine cellars are famous."

After that explanation, Sherlock lapsed into silence, reading a science journal. John looked out at the English countryside. Once free of London and the suburbs inside the M25, green fields and small villages took over. The train made a brief stop after passing through the light industrial landscape around Peterborough and then at Newark North station, before farmland reasserted its hold. These were the Cambridgeshire Fens- flat agricultural land criss-crossed with canals and drainage ditches.

John had never been to Cambridge, so he was curious when they arrived at the station. Of course, he'd heard about the place, seen pictures, stuff in films and TV, but the station was surprisingly modern and frankly, rather dull. Sherlock just said "Green Street" to the taxi driver, and turned on his phone, ignoring the journey into the centre of the university area.

The cabdriver's request "Is here all right?" was answered by Sherlock's terse "Yes".

They walked the last 150 meters, turning right onto Trinity Lane and then through a brick and stone gate. John stifled a giggle as he wondered whether it had served as a film set for one of the Harry Potter films. Sherlock obviously knew the way, and turned left to a glass fronted reception signed 'Porters Lodge'. A rather stern looking grey-haired small man in uniform came to the window, and asked whether they were tourists or had college business.

"Holmes and Watson; we are here to see the Master."

After consulting a PC screen, the man nodded, and handed through two badges. "You'll need these to access the rooms you've been allocated tonight. In Neville's Court, staircase four; it's a set with two bedrooms for visiting fellows. You swipe the key cards to get access to the staircase. I'll get someone to take you over."

"No need. I know the way." He collected the door keys and turned back to John, a smile on his face.

"Excuse me, gentlemen. The Master is expecting you at 4pm."

"Thank you, Hobbs."

That made the man stop for a second. "Holmes… oh, THAT Holmes. '97-98. Studies suspended. Come back to finish it off then?"

That comment wiped the smile off the brunet's face. Sherlock did not turn around to look at the Porter, but strode out with John trailing behind. When they passed through the arch and into the Great Court, John ground to a halt in amazement. It was MASSIVE, and dominated by an ornate stone carved round structure in the middle._ Why do I recognise this?_

Over his shoulder, Sherlock called out, "You've seen it before, in the movie _Chariots of Fire_. Come on, John; you can sightsee later."

Just before four o'clock, they came back across the Great Court to the Master's Lodge, an Elizabethan brick building that seemed at odds with the rest of the grey stone buildings on the other sides of the square. They were greeted at the door by a man in college livery, who took them upstairs into a drawing room. "The Master will be with you in just a moment. Please make yourselves comfortable." He poured them a cup of tea from the fine china service on the table between the two sofas. John took in the gold embossed ceiling and the ornamental fireplace, with the royal coat of arms carved into the stone. He recognised it from his army days, but it was subtly different. He was trying to spot the differences, when Sherlock followed the direction of his gaze and said, "Queen Elizabeth. The first one, not the current one. Her father founded the college."

Before John could react, a tall, spare man entered the room, brimming with nervous energy. "Please, don't get up. Holmes, Doctor Watson, I'm Hilton Soames, and I am so grateful to you for coming on such short notice." He sat down on the sofa opposite them, but could not be still, clearly agitated and distressed.

"We have had a very painful incident here, and really without your help, I fear that I have no idea what to do. There is so much at stake, but if you can solve this without getting the police involved then there is a chance we can spare the college and the University a great scandal."

Sherlock gave the man one of his slightly pained smiles. "Then let's not waste any time, Doctor Soames. Tell us what happened."

"Tomorrow is the examination for the John Pople Prize in Quantum Chemistry, to honour his 1998 Nobel Prize. You must have heard of the Pople prize, Sherlock. It was launched here in 2000. It's awarded every third year to the outstanding exam paper result. It's quite a prize- £50,000; one of the most substantial for an undergraduate for the whole university. The answers are adjudicated by a panel from the Chemistry faculty. I invigilate the exam, which is being held here in the Newton Library. "

He stopped for a moment and gave Sherlock a closer look. "Shame it wasn't around in your day. Might have made a difference; kept you interested enough."

Sherlock did not respond. Doctor Soames smiled a little tentatively at John. "I was Sherlock's Director of Studies here for the two years he was with us."

"If, as you say the matter is urgent, then it would be best not to waste any more time, Doctor Soames. Just the main points, please." This was delivered in a typically brusque baritone.

"Yes, well. The exam is being sat by 35 candidates, drawn from the very best students at the whole university. The papers were delivered to my study yesterday. I opened the pack to ensure that the material was printed correctly and counted to make sure that all 35 papers were there. The Prize panel is very particular to ensure that there is no chance of any student getting a prior look at the material, as that is about the only way one could cheat in this exam. So, I locked up the pack in my desk and went off to tea at Trinity Hall. I was sure I locked the door to the room as well. An hour later, when I returned, you can imagine my surprise when I found there was a key in the door, and the room unlocked. The only other key in existence is in Bannister's care- he's my man-servant. He's looked after me in college for the past ten years, and is utterly trustworthy, if a little forgetful these days; he retires at the end of term. Any other time, leaving my office door unlocked would not have mattered, but given the prize, it mattered."

"When I realised what had happened, I called Bannister and asked how his key came to be in the door. He said he had arrived with my usual tea tray at 4pm; he'd forgotten that I was to have tea out of college. As soon as he saw I wasn't there, he remembered my appointment, and left the room. Because of the tray, he didn't take his key with him, thinking he would return later. But he forgot. His attention to detail is not what it used to be."

As if he could no longer contain his agitation, Soames stood up and started to pace in front of the fireplace. "I went in and discovered that someone else had been in the room. The window seat cushion was awry, and the Turkish carpet rucked up. Both had been in order when I left. The curtain which I regularly draw to keep the sun off my desk had been pulled back. Bannister swears he saw nothing out of place when he popped his head in with the tea things. The desk drawer was still locked." Here he reached into his pocket and pulled a key ring out." There is only one key, fortunately. But, then I saw the sheet on the floor beside the side table by the window. It must have slipped down there when I was putting the others away. So, the Pople Prize paper could have been seen by anyone who came into the room when it was unlocked." The dismay on his face was clear.

"Bannister is devastated by the news, just distraught that his error could have led to this. So much so that I've sent him to his rooms; he's not fit for work today. You were shown in by one of the Porter's Lodge staff."

Soames resumed his pacing. "You see my dilemma. It's just…inexcusable. It throws the whole exam into question. I should inform the prize committee immediately, but I have held back for the shame of it. Either you must find the perpetrator, or else the exam will have to be postponed until a new paper can be set. This will have to be explained, and a cloud of scandal will descend on the college, and the University. The Pople Trustees might decide to take away the prize and award it at Carnegie Mellon University in Pittsburgh- that's where Pople actually did his work after graduating from here. There is so much at stake." He wrung his hands.

Sherlock stood, and John followed suit. "I'd like to see your study, if I may, Doctor Soames."

The man nodded and took them across the corridor. Unlocking the door, he started to step in, but Sherlock moved quickly to bar his path. "Please, the fewer people in the room, the more likely I will be able to spot some evidence that will lead us to the perpetrator."

He took a few steps into the room and to the side, then squatted down to look carefully at the carpet. "Did you touch anything after you discovered the problem?"

John and Soames stood in the doorway. The Master answered, "No, apart from checking the desk drawer for the other papers. And I did return the sheet to that drawer. Otherwise, it is as I saw it late yesterday afternoon."

Sherlock walked to the desk and examined its surface, using his pocket magnifier, then went to the window, where he looked out onto the immaculately cut lawn. "Across the Court, in the rooms over there, are there any students sitting the prize exam?"

"Oh, I hadn't thought of that! Yes, there must be. I will consult the list. Can I come in and get to my desk?" Sherlock nodded, then watched the Master unlock the drawer and remove the envelope. He drew the sheet of candidates out and scanned down the sheet.

"Yes- we have five Trinity students taking the exam, three of them are in Great Court rooms; Daulat Ras, she's an Indian student, brilliant mathematician. Then Miles McLaren. Yes- he's related to the Formula One McLarens, a bit of a lazy sod, but still an adequate chemist. And then Gerrard Gilchrist. He's here on an athletics scholarship, a decathalete. His father attended college here. Gilchrist may not make a first class degree, but hopes the prize will make up for it and help his physics career prospects."

John looked a little surprised. "Physics, mathematics- I thought it was a chemistry prize?"

"It is, Doctor Watson, but Pople is known for working at the intersection between chemistry, physics and mathematics. His trustees work hard to do justice to his legacy. He died in 2004. They set the exam question based on his private notes- which is also why it would be _so _embarrassing to have to tell them that our security has been compromised."

Sherlock stood thoughtfully at the window, his hands drawn up together under his chin. The Master just watched him, silently as the minutes ticked by.

Then abruptly, Sherlock turned back to the room. "I believe I can make progress on this matter for you."

Soames gave a sigh of relief. "You think one of them did this?" He looked across the quad.

"Perhaps, I need more data. Is it possible that the three of them will be dining in college tonight? Will there be an opportunity to observe them from the High Table?"

Soames beamed. "Of course, in fact, you can clap eyes on all thirty five of the candidates, because they are being entertained to a meal here as part of the process. I can ensure those three sit nearest, and you can even meet them at the drinks reception in the junior common room. The other Prize Panel members will be there, too."

"One last thing, Doctor Soames. I need a see a copy of the exam paper now. It will be a material factor in deducing which is the culprit."

Without a word, the Master reached into the packet of papers, withdrew one and handed it over. As Sherlock scanned down the paper, a smile starting to form on his lips. By the time he reached the bottom of the sheet, he was grinning. "Excellent, excellent question and it will be relatively straight forward to catch this cheat."

That night John was treated to his first ever High Table. Dining in college at his university had been a case of grabbing food from the cafeteria, but as most of his classes had been at one or other teaching hospital, that was most often a hospital cafeteria. Medical students at London University endured a five year course that left little time or energy left for ceremonial functions. His social life had consisted of taking girl friends to see a film, or rugby games with the boys. So, he was somewhat intimidated when he and Sherlock went into the JCR to be greeted by a sea of black gowned smart-suited young people.

If John felt intellectually challenged by the undergraduates, he was positively intimidated by the academics. The Master took them in hand and started making introductions. After ten minutes, John was reeling from trying to keep them all straight. _Only place I've been where there are more doctors than at a hospital_. For a man who professed to dislike crowds of people he didn't know, Sherlock seemed oddly at home. That is, until one of the dons to whom Soames introduced him started to smile, rather maliciously. "You don't remember me, do you, Holmes? I was in your inorganic lab seminar group. You always thought you were too clever by half to do things the way the experiments were set out. Still, I suppose a little smattering of chemistry makes you sound the part in your trade. No wonder the tabloids love to call you Boffin." The sneer was evident on the chubby man's face.

For a moment, Sherlock just went still. John could see him deciding whether the effort was worth it. John murmured quietly, "he's a prat, just ignore him."

The brunet started to turn away. But the don wasn't finished. "Probably can't remember me because you were so wasted on cocaine that it was amazing that you could even find the lab."

That was enough. The detective turned to his tormentor. "Oh, I remember you, Charles Quinton. Who could forget the final year student forced to repeat that class because your ineptitude meant you only managed to pass the practical on the third and final resit attempt? Nice to see that your father's generous contribution to the Biomedical Research Centre was conditional on finding you a research fellowship. After all, we both know that your post would never have been awarded on merit. Your family has always been so _supportive_ of your career, haven't they?"

Before the red-faced academic could respond, John steered Sherlock away. At the drinks table, he looked at his friend. "The guy's an idiot, don't waste the energy."

Sherlock surveyed the people in the room. "Most of them _are_ idiots, John. That is the reason why I left." But John noticed how quiet his friend was for the rest of the evening. Trinity College's dining hall was an astounding room, and John's eyes kept wandering up to the hammer-beamed roof. The enormous oil painting behind the high table was of Henry the Eighth, and beneath his royal gaze, the finest chemistry undergraduates at Cambridge were fed a three course meal. John enjoyed his roast duck breast in a redcurrant and burgundy sauce. He noticed that Sherlock ate very little, and put his hand across the crystal wine glass each time the waiter appeared at his elbow. The doctor was kept entertained by a talkative and attractive red-haired woman in her thirties on his left, a research fellow in medical bioengineering. She was fascinated to hear his stories about battlefield surgery techniques in Afghanistan. His attempts to involve Sherlock in the discussion were politely but firmly deflected. Apart from the occasional word with the Master, the brunet spent his time observing the students.

The long table at which they were seated was made for such scrutiny. The academics and guests sat all in a row on one side, facing out to three long perpendicular rows of student diners. It was actually a 'high' table, up on a dais about fifteen inches above the rest of the hall level, which gave them a perfect view of the students. Sherlock was focussing most of his attention on the three that Soames pointed out to him; Daulat, Miles and Gerrard.

When the main course plates were taken away, Sherlock excused himself. "I will see you back at the rooms, John. Take your time. Port and coffee in the SCR will follow the pudding course. I will be investigating the three suspects' rooms, together with Hobbs, the Head Porter."

When John got back to the Neville court rooms, it was late. The wine, the port, the excellent food and the red-head's laughter just pushed him into a haze of contentment. He found Sherlock sitting at a table in the shared living room between the two single bedrooms. He had a pad and pencil out and was flipping a penny coin.

"Bored? Sorry, things just…went on a bit."

"They always do at Cambridge, which is why I was glad to have an excuse to leave early. And, I'm not bored."

John looked at a second coin which now lay flat on the pad, brown and duller than the one in Sherlock's fingers. The brown one on the table was slightly thinner in width. "An old coin?"

"Yes. I'll explain tomorrow."

"Solved it then?"

"Good night, John. Pleasant dreams."

Whether it was the wine or the food, John managed eight hours of blissful sleep. He was woken by the sound of Sherlock in the shared living room. "Come on, John. I've been up an hour and we need to put Soames out of his misery. He will be in a dreadful fidget until we can lay his mind at rest. Can you do without breakfast?"

Fifteen minutes later, they made their way to the Master's Lodge, where they found Soames anxiously pacing. His face was lined with worry and it was clear he had not slept at all. Unshaven and clothes thrown on, he seemed on the edge of exhaustion. "Ah, Holmes. Have you come to the rescue? Or do I have to call the Panel to postpone the exam?"

Sherlock smiled. "Let it proceed, by all means."

"But, is there a cheat? Who is the rascal?"

"Summon your servant, Bannister. I must start with him before we confront the guilty party."

"He's back on duty this morning, so I can call him in now."

When the elderly and slightly stooped man came into the study, he took in the presence of Holmes and Watson, and his face fell. The Master directed him to take a chair, and then leaned back in his chair behind his desk with a set frown.

Sherlock looked down at the servant. "Now, Bannister. Will you please tell us the truth of yesterday's incident?"

The man turned white, to the roots of his hair. "I have told the Master everything."

"Nothing to add then?" It was mildly said, but with more than a hint of menace in the baritone. For a moment, all John could think of was Mycroft. _He's channelling his brother to put the fear of God into this poor sod. _

The man was clearly shaken, but he stood fast. "No, sir."

"Ah, that's a pity, Bannister. I thought to give you a chance to put it right. You've served the college well and it seems sad to go out on such a sour note. Still, remain where you are, please. Doctor Soames, can I ask you to go up to the room of young Gilchrist, and escort him down here now?"

The Master left, and Sherlock paced. The servant's eyes followed his tall figure back and forth, his obvious distress rising with every step. The doctor began to worry that he might have heart trouble.

When Soames returned, the student followed him into the room. He was athletic in build with a fine spring in his step, until his blue eyes caught sight of the other occupants of the study. "Oh, Bannister. Don't tell me. How did they know?"

"I've not betrayed you, young master. I haven't said a word. They can't prove a thing."

Sherlock frowned and reached into his pocket. "Then perhaps you can explain this, which I found on the desk in your rooms." He pulled a metal bar that was about three inches long from his pocket. He showed it to the Master. Soames looked at it for a moment, and then he nodded. "Yes- a magnetic stirrer. That would do."

Gilchrist just whispered, "_damn."_

The old servant turned to Soames now, and in a pleading voice, began to confess. "It's all my fault, sir. I brought the tea tray in as I said, and that's when I spotted the paper. I told the boy to come down and use my key to let himself in and take a look. He _needs_ to win this prize, sir, he really does. His father died at the start of last term and the house has been repossessed. The College Bursar says he's not eligible for financial help, because of his family wealth. But it's all tied up in contested property deals; will take years for probate to come through. He's not got a stitch of ready money to his name, and I can't afford his fees anymore. It was hard enough this term, but next, when I am on a pension, I just can't do it."

The effect of this speech on the young man was devastating. His eyes filled and he let a strangled gasp out. "Stop it, Bannister; this won't do. You can't risk your position and your pension." He turned to Sherlock. "It's my fault. All my fault. He told me of the opportunity and like a fool, I took it. Came in and found the sheet, took it over to the window to take a photo with my phone, needed the extra light. If you ask me why I was tempted to cheat, well, I have to be honest about that. I'm desperate, in debt and no hope of paying my fees. Without the prize, I will have to quit and take whatever job I can get. Just don't make him suffer; he's been too kind to me."

Sherlock turned away from the bookcase, which he had been surveying during the emotional outbursts of the old man and the student.

"Bannister, tell us how you know the Gilchrist family. A former employer perhaps?" The old man just nodded, his face now wet with tears. "And some misguided sense of loyalty led you to think that cheating was the best way to help express that loyalty." Another nod.

"Doctor Soames, you have your confession. The prize exam can proceed, and the reputation of the college and the Pople Prize is intact. Gilchrist, based on the set of calculations I found on the pad under the magnet, you do have the makings of a competent chemist, if not a very bright one. Perhaps a suspension of studies, until such time as you have earned the fees you need through hard work at a lab bench somewhere in the Cambridge Science Park- perhaps that is a fitting enough punishment."

Soames nodded his agreement. "Bannister, go home. We will talk about moving your retirement date closer; it was only a month away in any case. Gilchrist, take him home and then return to college long enough to clear your room. I will process the paperwork for the suspension."

When the two unfortunates left, Soames turned to Sherlock. "Thank you, from the bottom of my heart. A formal rustication would require the circumstances to come out in public, and that would be harmful to all concerned. This is the best solution, and one I could not have foreseen from the depths of my despair yesterday. You have saved the day, Holmes."

"It was nothing. Really rather straightforward, as cases go." He made to leave, and John stood.

"Wait…" The Master came around his desk and drew up to the tall brunet. "I've been meaning to say this for, well, nearly sixteen years. I am sorry we couldn't keep you interested. I was never one of your nay-sayers, although there were some on the College council who wanted you to be sent down for good. It was kind of you to be willing to help us, when the College did not serve you as well as it might have. Thank you."

He offered his hand. Sherlock looked down at the hand for a moment, and then shook it.

As they left the room, Soames said one more thing. "You've solved it, haven't you? You've recalculated the Bernoulli formula to take into account the magnetic force?" Sherlock just smirked.

On the train home, Sherlock buried his nose in the journal article again. John waited until they were out in the countryside again. "Okay, now that there is no one within ear shot who is going to laugh at my ignorance, I have to know. What was all that about? How does a magnet found in a student's room make him guilty?"

The detective gave a wry, small smile. "The Pople prize exam question was set around the physics of flipping a coin. It's a long standing tradition- vast numbers of academic papers have been written on the subject. It may sound trivial, but actually it is a microcosm of chemistry, physics and mathematics in a single understandable activity. The question consisted of two different data sets, a table of probabilities relating to the pre-decimal pence, the second to the current penny. The first coin is between 95.5 and 97% copper, the latter is less than 5% copper plating around a steel coin that is slightly thicker to ensure the weight is the same as the pre-1992 pennies in circulation."

"So that's what you were doing with the coins last night, testing a theory?

"Yes. The second table on the exam paper shows a deviation in the probabilities from what one would expect, even with the metallic difference and the change in thickness. The answer is that who or what was flipping the coin was cheating, by using a magnet to influence the odds. From the data it was possible to calculate the nature of the magnet effect- weak- and to deduce its character. The prize will be won today by the student who is best able to recalculate the Bernoulli formula to take that additional factor into account. Makes me wish that John Pople had taught here instead of going to the USA. It's quite clever, actually." He turned back to his journal article and resumed reading.

John sat back in his seat and smiled at the Cambridgeshire countryside_. It takes one to know one._


	20. Chapter 20

**Author's Note- **apologies for the week long delay. I have been working on another story that I will start posting next week, called Musgrave Blaze. Now that it is 20,000 words along, I am able to juggle it with Periodic Tales again.

* * *

**Chapter Twenty**

**Sulphur S 16 **

_A non-metallic mineral, __elemental sulphur is a bright yellow crystalline when at room temperature. Disulfide compounds are largely responsible for the mechanical strength of the protein keratin, found in the outer layer of skin, hair and feathers, and the element contributes to their pungent odour when burned._

* * *

John was tired, worn out, knackered. It had been a brute of a day at the clinic. The annual "Flu jab-a–thon". They'd seen over 200 patients, with three doctors and nurses taking a continuous stream of elderly patients through the process. Like a factory assembly line, the receptionist ticked off names, handed them numbers in sequence printed on yellow, green or blue tickets that people normally associated with raffle prizes. John drew the blue tickets- and he swore that the nurse had it in for him, and gave out blue tickets to every awkward, cantankerous old fool she got through the clinic door. He was certain that his dreams would be filled with the explanation of what the jab did to protect the elderly person; he certainly knew the patter as well as a stage actor knew their lines.

The only variation to the routine occurred when on three occasions a patient queuing in the blue line fell over. Two were just old and doddery, and found standing for so long hard. Another passed out, giving John a welcome chance to use his diagnostic skills rather than his injection technique. A simple case of low blood sugar, easily remedied with a carton of orange juice and a biscuit.

So, the last thing he wanted was any drama on the home front. A nice cup of tea, a take-away meal, crap telly and a warm bed- in that order, no deviation.

But by the time he'd taken his second step from the front door onto Baker Street, he knew his chances of that were slim in the extreme. Mrs Hudson greeted him in the hallway with a pained expression. "John, you really need to tell him to stop this sort of experiment. I mean, just take a sniff!"

He didn't need her admonishment; he could smell the problem from the moment he crossed the threshold. The most revolting combination of rotten eggs and burning hair was coming down the stairs from the flat.

"I've opened all the windows in my flat- it's freezing! I had Mrs Turner over for tea, and she had the nerve to complain about the smell, saying her lodgers never did anything like this."

John went up the stairs and gingerly pushed open the door into the flat. He swallowed the bile that threatened to come up his throat; it really was the most nauseating scent he'd come across- even a badly decomposed body at Barts managed to be more tolerable than this. Was it his imagination, or was there a haze of…something that made the air seem murky as well as smell disgusting?

He noticed that both windows overlooking Baker Street were wide open. Turning back to the kitchen, he saw an extraordinary sight. To start with, Sherlock was virtually naked- just wearing underpants, goggles and…was that a set of nose-plugs? John was used to his flatmate's mad scientist days, but this just took the biscuit, especially since it was so cold in the flat that his breath clouded. He watched as Sherlock touched the blue flame of a blowtorch to a sample of…something stretched between metal clips on a table-top scaffold.

Instantly, the stretchy piece of what looked like leather scorched, charred and then emitted smoke. A waft of something even more revolting reached John's nose, which was actually beginning to hurt.

The doctor lost his temper. "Sherlock! What the _fuck_ are you doing? I thought you were the one with the hypersensitive sense of smell!? How can you just stand there when that is just so revolting?"

"I'm comparing the odoriferous nature of sulphur reduction compared to sulphur combustion." This was uttered in a most peculiarly nasal sounding baritone, the effect of the nose plug.

While John digested Sherlock's bland statement, he had to ask. "You must be freezing. Why are you…um..naked?"

"I'm not. As you can well see, I am wearing pants in deference to what others would think of as decency, although to be honest it is a nuisance, because I will have to throw them away. The natural fibres in my clothing will retain the scent, even after washing. My skin and hair will not."

John looked around at the room. "Well, that's _you_ sorted, but what about the rest of the flat?"

"As Mrs Hudson's concept of carpet, curtains and soft furnishings have a high proportion of man-made fibres, the scent will dissipate within a couple of hours." The brunet turned off the blow torch and then bent over the kitchen table, putting his nose close to the now blackened specimen. He took a breath, and then removed his nose plugs. John watched as the man's face twitched, his eyes started to water and his features took on a look of disgust.

"If you don't need those nose plugs, I'll have them." John tried to keep his voice calm, but it was difficult. Without a word, Sherlock handed him the beige plastic swimmer's equipment.

Now John was the one with the nasal twang. "Just what is all this in aid of?" Even to his ears, his voice sounded like some sort of cartoon character.

"Case, John. I wouldn't willingly be doing this if someone's alibi didn't require it. Should be done with this phase in a couple of minutes."

"Right, then. I will just have to make myself scarce for a while."

"The fumes are heavier than air, John. Your bedroom upstairs will be much better, and your nose will give up after a while- nasal receptors get overloaded and shut down. That's why I need the nose plugs back; I _need_ to be able to smell these, and distinguish between them. So I have to wait fifteen minutes between tests for the sense of smell to return."

Reluctantly, the doctor pulled the plugs from his nose, and started to head into the hall. Anything to get away from the smell. He couldn't face having to stand in the kitchen long enough to make himself a cup of tea. But, he thought he might grab a glass of milk. He went around the eccentric scientist, eying the charred remains. "What is it?"

"You don't want to know; really, John." The doctor decided to take his word for it. Sherlock was writing something in his notebook, as John reached the fridge and started to open the door. As he did so, Sherlock said. "I wouldn't do that, if I were you." The nose plugs were back on and it sounded weirder than ever.

The connection between John's brain and his hand seemed to have been slowed by the stink of the experiment, and impulsion kept him going as he tried to understand his flatmate's warning. The door of the fridge was open by the time he realised it was too late. What came out of the fridge made John actually gag in revulsion. It was the most disgusting scent that John had ever come across. He slammed the door shut and turned back to his flatmate. In a voice tinged with horror, he asked "What died?"

Sherlock smirked. "Nothing. If it had, you'd be smelling putrescene or cadaverine. _That_ scent in there is something entirely different from decomposition, John." He wrinkled his nose; "I can't talk and breathe through my mouth at the same time." He pulled the nose plugs off again. " What's going on in the fridge is sulphur reduction- what happens when bacterial enzymes digest a wide variety of foodstuffs. This one is cabbage mostly, leavened with onion, garlic and chive, a handful of Brussels sprouts and one of cashew nuts. The recipe is simple- just add _e coli_ bacteria and _voila_- think of the result as what goes on in your digestive tract. It releases hydrogen sulphide, amongst other trace sulphur compounds."

"Sherlock, whatever is going on in that fridge smells like shit."

"Well, yes, _of course_ it does. That's what happens in your gut. Didn't you learn anything in medical school? I'm not interested in the indole and scatole released, just the sulphur. A lot of the sulphur compounds are volatile, and emerge as flatus or bad breath. What you are smelling in the fridge is methyl mercaptan, reputably the world's smelliest molecule, and a key ingredient of excrement."

John stifled a giggled. "I've heard Lestrade complain about shit cases before, but, what does shit have to do with a case?"

Sherlock looked up, his puzzlement clear through the goggles. "Who said anything about a case involving shit? I am interested in the methyl mercaptan- that's CH(4)S. Although it's a natural substance found in the blood, brain and other tissues of animals and people, it's toxic in sufficient quantities. It binds to cell membranes, and the iron in enzymes with haem- so it messes up human respiration and inhibits mitochondrial electron transfer. Hydrogen sulphide causes respiratory distress," here he gestured at the still smoking specimen, "but exposure for only a few minutes to high concentrations of methyl mercaptan can kill within forty five minutes because it destroys both respiration and liver function." The detective smirked, "In short, John, what's in the fridge will kill you before what's in the air."

"And why are _we _dicing with death, Sherlock?"

The brunet gave an involuntary shiver; with the windows wide open, it was cold in the flat. "The case, John. A woman has been murdered, but there is no trace of a wound. Cause of death is acute respiratory distress and liver failure. The medical pathologist has said that she died of complications from her cancer treatment interacting with sulphur fumes. Anderson made up some daft excuse to explain the traces of burned sulphur residue in the greenhouse where she died, saying she was trying to kill off powdery mildew fungus. I think that was a smokescreen set up by the murderer."

He sniffed again at the specimen. "The other people on the crime scene didn't smell what I did- which was a trace of methyl mercaptan, rather than sulphur dioxide."

"If it smells like what's in the fridge, how the hell could anyone be stupid enough to eat or drink something laced with it?"

""Use your imagination, John. Inside a syringe, you wouldn't be able to smell it. She was being treated for ovarian cancer and making a good recovery. I think her husband decided he'd rather she died, so managed to introduce a dose of methyl mecaptan into her intraperitoneal injection site. It would have been absorbed by the mesentery veins and then gathered into the portal vein of the liver. The husband is a chemist working in the petrochemical industry and he would know the effects of the compound. So I am trying to see if it is possible to grow my own methyl captan in sufficient concentration. That fact, plus opportunity and his obvious motive should be enough to convince the coroner to give an open verdict or, better still, declare it as unlawful death."

The doctor thought about the lengths to which Sherlock was willing to go to prove his case. "Tell me that you will thoroughly decontaminate, sterilise and deodorise the fridge as soon as you are done."

"Of course, John. I am hypersensitive to scent, so am even more highly motivated than you are to finish this."

"Well, hurry up and get some clothes on before you catch your death of a cold or flu."

Sherlock rolled his eyes. "Given what you've been doing all day, _doctor_, you are more likely to have been exposed to influenza germs than me. Besides, I defy any flu-ridden person to come within a couple of meters of me at the moment. The smell alone gives me protection." He unclipped the specimen from the scaffold and waved in front of the doctor, as is warding off evil. John laughed at the absurdity of the scene, but realised that, as usual, his flatmate was right.

oOo

Esther Cohen's shift had been a long one, and she closed her locker door at Royal Bethlam Hospital with a sigh of relief. She leaned her forehead against the cool metal and closed her eyes for a moment. One case after another- starting with a sixteen year old boy high on drugs and screaming his lungs out. He had resisted arrest, attacked the police officer, biting him so hard that it not only bled but nearly broke the man's finger. He was still screaming obscenities as they brought him in, handcuffed and taped down to the ambulance back board- not because of any injury, just to protect the rig's crew from being attacked. Sixteen was young for schizophrenia, but all the signs were there.

Hallucinating teenagers were hard to talk to, even after narcan and sedation, but the next patient had been even harder- a three year old boy, showing signs of physical abuse showed up at the Emergency Department. She loathed that sort of case- arguing with parents, either of whom could be the perpetrator, negotiating with social services to take the child into care, and notifying the police. The paperwork alone was a nightmare, when all she really wanted to do was deal with the pitiful results- a bruised and battered toddler, who wasn't willing to talk.

Those cases, as stressful as they were, did not upset her as much as the last one, however. She was literally half way out the door after clocking off when the ambulance arrived. A young girl had been found wandering in a park in Beckenham, naked but covered in excrement and blood. Esther had been called in to help restrain her, and ended up covered in the mess, too. She reeked, but a shower would have to wait, because whenever the nurses tried to wash the patient, she started screaming. The young girl was hysterical with fear, to the point where she wouldn't tell a soul her name.

Eventually after two hours of patient work, Esther had pieced together the story. Amina had just started her periods and had been dragged by a group of Asian boys into a back alley. They called her a slut and unclean, and then ripped her clothes off and covered her in dog shit. She had wet herself, thinking they were going to kill her, but they just beat her up instead. Her crime? She had been seen in the park talking to one of the neighbours- a white teenager. "They said I was a stain on the honour of the community. I was shit, I had to smell of shit; they forced me to eat it, too." By the end of the session, Esther had calmed the child down enough to be touched. To demonstrate that there was nothing to be ashamed of, Esther had cuddled the child and got her to agree to take a shower by herself. When Amina took the offered tablets and drifted off to sleep, Esther gave a sigh of relief. She'd be back in eight hours to start the process of treating her; in the meantime, photographs were being circulated by the police in the hope of someone coming forward to identify her.

All in, the thirty six hours on duty and on call had taken a toll on her sense of well-being. It was days –and nights- like these when she began to think that paediatric psychiatry might not be where she wanted to end up in her medical career. She stank of shit and blood herself, but rather than clean up and change at the hospital, all she wanted was to go home. At least on the bike ride to her flat she would not offend anyone- public transport was impossible when she smelled like this. She pedalled up the tree-lined Monks Orchard Road, around the roundabout and then on up South Eden Park Road, turning right onto Cresswell Drive. Her flat was in Osborne House, where most of the occupants worked in the nearby Langley Court Research Laboratories. The studio apartment was all she could afford, but she preferred it to a larger one which would have meant a flat-share.

She threw her keys onto the tiny hall table and hung up her coat on the wall rack, then kicked off her shoes as she walked down the corridor between the galley kitchen and her bathroom. She started unbuttoning her blouse as she walked; that shower was going to be _extremely_ welcome.

Her hand fumbled the button as she realised that there was a man standing at the window, looking out across the parkland. The idea of a stranger in her flat just made her brain seize up for a moment, then she was frantically re-buttoning her shirt and backpedalling towards the phone that was also on the hall table.

"There is no need for alarm, Doctor Cohen. I am not a burglar or a stalker, just someone who wants a professional opinion." There was something in his confident baritone that made her hesitate before she picked up the phone. The man's voice was deep, but calm. No, somewhat curious, too, as if he was slightly bemused. She stared at him, trying to identify him. He was tall, well-built but tending towards heavy now that he was middle-aged, with reddish-brown hair. For a moment, she wondered if she'd seen him before somewhere, perhaps the parent of a patient at the hospital? She hoped not- as today's cases showed, parents were not always on the side of the children she treated, and he could be seeking revenge for her role in taking a child into care.

"Who are you?" She pulled the handset from its cradle, punched in the emergency numbers and held her finger poised to hit dial.

"I'm Richard Holmes, and I've been wanting to speak to you for some time about one of your patients."

_Of course_. Now that she had the connection, she could see the similarities with Mycroft Holmes. But she saw nothing of Sherlock in his features. She put the phone back down, and returned to face the man. With her hands on her hips, she glared at him. "How the hell did you get in here?"

"That's irrelevant, Doctor. It's a bit more seemly than being seen loitering outside in the hall. Your neighbours would be suspicious."

"Damn right and for good reason. So, why didn't you do what most normal people do- telephone, make an appointment at the hospital, or have the courtesy to write a letter?" She might be small and a lot younger than he was, but she was angry enough at his intrusion to make up for it.

He looked bemused at her posturing. "None of those approaches would have told me even a fraction of what this place tells me about you. And, given your role as my son's psychiatrist, I find it useful to know more about you than can be gathered from professional credentials. For example, the fact that your current work is rather _hands on_, if the stench you are emitting is that of a patient rather than some unfortunate personal accident."

She wanted to kick him out. She found his attitude atrocious and just a tad threatening. But, there was a little thought kicking around in her head- _this might be the best opportunity to find out just who this guy really is, and why he has had such a toxic effect on both his sons._

"Sit down." It was an order, and she wanted to know if he would be sensible enough to give her some degree of control. If not, then she would chuck him out. He cocked his head at her tone, and gave her the slightest smile. That broadened as he chose her favourite chair and sat down.

_Okay, you want to play mind games with me, Mr Holmes? _She turned her back on him and went into the galley kitchen, filling the kettle and switching it on. He could wait. She was going to have a cup of tea and let him be damned. While the tea bag steeped, she went into the bathroom, stripped off her outer clothing and stuffed them into a plastic bag which she tied up. No need to make everything in the hamper smell. Then she pulled on her long fluffy bathrobe. Collecting her cup of tea, then, and only then, did she return to the living room to sit down on the sofa, all the while making it clear that she was _not_ getting him anything to drink. She watched him watching her. She said nothing, waiting for him to start.

His eyes reminded her of Mycroft- hard and very determined. Just as he drew breath to start speaking, she interrupted. "He takes after you."

The eyes grew even colder. "I presume you mean my elder son. There is nothing of me in the younger."

"Oh, he's not legitimate then? Did your wife have an affair?" She said it as offhand as she could manage.

A muscle in his jaw tightened, but he did not rise to the bait. "No, DNA does not lie. Genetically speaking, he should have been perfect, but something failed between blueprint and actual production. A manufacturing defect- statistically speaking, they do happen, even with the best designs."

His cold-bloodedness made her almost flinch; how callous could a parent get about an autistic child?

He continued, "What has Mycroft told you about Sherlock's behavioural disorders?"

"He hasn't had to _tell_ me much; I've had access to your youngest son's medical records, and I've seen Sherlock. Mycroft let me form my own diagnosis, rather than trying to prejudice me."

Richard Holmes had a commanding presence, even when seated he exuded a confident power- the authority of a man who was used to leading, one who expected obedience. He didn't like the quiet criticism in Esther's tone.

"You've seen Sherlock on three occasions. Twice at that geriatric facility your uncle runs- oh yes, I did manage to track down where you hid him. And then for a more extended period when you spent four days at _my_ home. A waste of your time; I do hope you weren't charging Mycroft by the hour. He can be rather naïve about such things, but then he is young and inexperienced when it comes to procuring medical support for a defective child." Everything in that sentence was designed to make clear his disapproval.

She needed to nip that in the bud. "Mr Holmes, I am not contracted to you, and, to be blunt, what you think about my involvement in Sherlock's treatment doesn't matter."

He smirked and held up his hands in mock surrender. "I am not here to quarrel, Doctor Cohen, just to understand. In less than a month, Mycroft returns to Oxford. Quite pragmatically, he is negotiating what will happen to his brother's care when he resumes his studies and leaves the boy behind. I have already pointed out to him that he cannot legally stop me from returning to my home in Sussex. I have been willing to spend the summer at the London townhouse, but that's a temporary measure. My business interests involve corporate hospitality at the larger house. I have tried to convince Mycroft that the best solution for Sherlock is an institution capable of meeting his needs- a special school that can deal with children of his kind- but he insists that the boy should remain in familiar surroundings. Mycroft has spent the last month putting in place a series of carers and tutors, people who will keep the child occupied."

He leaned forward in the chair to scrutinise her more intently. "You are one of those people, so forgive me, but I am a little curious to know more about you, and why Mycroft thinks you will succeed any better than the shockingly large number of other medical professionals who have tried in the past. My wife, you see, used to think that the boy could be 'fixed' somehow. I told her it was hopeless and a waste of her time, but alas she saw things differently. It cost her health and her happiness, and eventually, her life."

Esther sipped her tea. Mycroft had discussed the arrangement with her. She agreed that after such a lengthy stay in an institution, Sherlock needed familiar territory, even if it meant being near his father. "I have no doubt that Sherlock will do his level best to stay out of your way, Mr Holmes. By what I was able to observe during my visit, he has developed a large number of avoidance strategies that work remarkably well. By the way, you may be surprised that for someone diagnosed as autistic, who shouldn't be able to understand emotions very well, Sherlock believes that you _hate_ him."

The man snorted in derision. "I don't hate him, Doctor Cohen. I don't care enough to waste that level of emotion on him. The boy mistakes neglect for concern. It is said that autistics are unable to form emotional attachments; well, it works the other way, too. It is nigh on impossible to form a productive emotional relationship with someone like Sherlock, so I have never attempted it."

He said this with no malice, in just a pragmatic tone. "The house is large enough that our paths won't cross. He will have the freedom of the west wing, and the house and grounds when there is no one visiting me. I tend to be away a lot on business trips. He has become rather good over the years at avoiding me, and I certainly do not seek his company. Mycroft knows it will work, because he knows both me and his brother."

She put her empty cup down on the coffee table. "Why does it matter what Mycroft thinks of the arrangement?"

That provoked a slight smile. "Because he is my son and heir. He is Lord Mycroft, Viscount of Sherrinford, and he will go far in this world. Don't take my word for it, lest you think I am being a doting father. His tutors at Eton and Oxford are just as sure as I am about his promise. I would not have Sherlock come between us. He isn't worth it. So, I have waved the white flag of surrender. If Mycroft thinks he is being noble, doing the right thing by his little brother, then I cannot change that idea. I don't really have to do anything but wait. Sooner or later, Mycroft will come to realise Sherlock's limitations, and that he is a burden that need not be borne. Then he will shut him away and get on with his life. My elder son is certainly no fool. Time will come when he will put away sentimental loyalties."

The man got to his feet gracefully. Aware of his towering height compared to her sitting on the sofa, she stood up, too.

"So, by all means, Doctor Cohen, do whatever you think is best. Please forgive me if I think it unlikely that you will be able to help. You are a paediatric psychiatrist with no private practice experience, whose work to date consists of hospital consultations with patients you rarely if ever see again and whom you cannot possibly treat through any consistent therapy. Your academic research was well-respected at Oxford, but Sherlock is not some ordinary child who can be talked out of misbehaving. You won't be able to 'fix' him, Doctor Cohen. He's not fixable."

He started for the door. "I won't thank you for your hospitality, Doctor Cohen, as my unorthodox entry made you forget your manners. It is possible that we might bump into each other at the house in Surrey, where I will try not to reciprocate. Until then, I will say goodbye."

_Patronising bastard._ Not for the first time, Esther Cohen realised that helping Sherlock was something she really, really wanted to do. Not just for the boy's sake, nor for Mycroft's, but now she realised what a personal pleasure it would be to make Richard Holmes learn just how wrong he was. She headed for the shower; she had an overwhelming need to feel clean again.

* * *

Please review. After days without input (yes, I KNOW it's my fault for not posting!) I am in need of feedback.


	21. Chapter 21

**Chapter Twenty One**

**Sulphur (Part Two)**

_Known since ancient times, biblical references refer to sulphur as brimstone, or burn stone in English, since 1777, an important ingredient in black gunpowder, which is a combination of potassium nitrate supplying oxygen for the combustion, charcoal which provides carbon for the reaction and sulphur,_ _which, while also serving as a fuel, lowers the temperature required to ignite the mixture, thereby increasing the rate of__ combustion._

* * *

Frank Wallace lifted the Purdey .410 over-and-under shotgun. At four and half pounds in weight, it was perfect for the twelve year old boy now standing a little nervously in front of him. "It was your mother's first Purdey, made for her she was sixteen. She was a good shot, in fact better than your father, but then she'd been shooting over this ground all her life."

It was mid-September, and in less than two weeks, the pheasant season would open. Already partridges had been taken on the estate. Richard Holmes was a keen enthusiast, and almost every weekend from mid-September to the end of January, he brought down to Sussex his clients and contacts important to his business interests. Saturday corporate shooting days on the estate were eagerly sought; the invitations were almost always accepted.

In sharp contrast, on Thursdays during the season the estate's A syndicate had offered a different kind of experience for some of the finest shots in the country. This had been the preserve of the Viscountess, who cared little for the sort of men who were her husband's business contacts. Those people liked to _look_ the part, in their brand new country tweeds, but they were more interested in business than sport. An invitation to join her Thursday syndicate was one of the most sought after in the shooting fraternity, and openings were as rare as hen's teeth. These people were dedicated, and they still shot despite her death two years ago.

Mycroft had asked the gamekeeper to see if Sherlock was interested and able to take up the pasttime. "The noise may alarm him, and the scent of the spent cartridges might be a bit overwhelming at first. If he can cope with it, however, he might find it an interesting challenge. It will help his eye-hand coordination."

The staff on the estate knew the younger boy to be developmentally challenged; "not quite right, but harmless" was how most of the staff thought of Sherlock. But the gamekeeper had always made time for the young boy, because he was so curious about the wildlife and the estate grounds. For the past five years, he'd been willing to have the youngster follow him around on his daily duties, tracking foxes' dens, putting the young birds down into the pens before they could fly, daily rounds of feeding and watering them, as well as the more physical work, clearing the rides through thick cover, making sure that the pegs where the guns would stand were ready for the season. He never talked much, but he did ask questions, which Frank was happy to answer. Above all, Sherlock enjoyed being with the dogs, working the spaniels with the other beaters to flush birds out of cover during last year's season and even helping to train the retrievers during the summer. He liked being outdoors. His brother was more interested in books than birds, so Sherlock gravitated towards the gamekeeper far more than Mycroft had when he was the same age.

For the past week, Frank Wallace had spent an hour or so a day with Sherlock, showing him how the gun worked, and letting him get the feel of it unloaded. He'd been amused to find the boy had pocketed a cartridge without him knowing, and then took it apart to see how the pellets, wadding and gunpowder worked inside. The gamekeeper noted the difference between the two brothers. Mycroft had been taught to shoot by his father, but it was the Viscountess who insisted that the elder boy come to Wallace for lessons- "you need to un-teach him; I fear he has picked up a few bad habits from Richard." Now Mycroft was a good enough shot, and if he could manage to get away from university on the weekends, he was a regular on his father's line-up of guns- in part to build the boy's network of influential contacts.

Sherlock's interest in shooting was in the mechanics and the science. He wanted to know how things _worked_- what was the chemistry in the cartridge that made the explosive thrust that spread the shot out? How did the gun initiate the procedure, what was the role of the firing pin? How was it connected to the trigger? Under Frank's tuition, he had taken one of the gamekeeper's old shotguns to pieces and then put it back together again, so he would understand how it all fit together. In between sessions, Sherlock was reading in the library and learning everything he could. So many questions to be answered that it was only now, a week later, that he was actually going to fire the weapon.

Frank took him to a section of the woods, a natural amphitheatre some twenty feet into a hillside. It was an area that was used for clay pigeon shooting out of season, secluded and safely away from where anyone might stray into range.

"So, Sherlock, remind me how it works again?"

"The firing pin strikes the primer in the cartridge, the primer ignites the powder, the powder has sulphur in it that burns and turns into a gas, the gas propels the shot down the barrel, the shot exits the barrel and then the column of shot gets affected by gravity and begins at seven meters to string out and form the circular pattern." This came out at in one breath.

Frank smiled and handed him the weapon. "Show me the stance."

Sherlock had spent the past week watching exactly how Frank stood when he fired the gun. It was all part of the process of getting the lad used to the sound and the smell of the gun going off. Even with ear defenders, the noise was startlingly loud, but he'd eventually been able to relax and not flinch every time the gun went off in his vicinity.

The twelve year old was still a bit weedy, starting to put on some height, but nothing like his brother, who had taken after their father. Mycroft was bigger-boned and with a sturdier build when he was twelve, taller, too. The younger boy now put his left foot slightly forward of his right, lifted the Purdey and placed the butt of the shotgun tightly into the inside of the pocket of his shoulder, resting slightly on the pectoral muscle. He made sure his cheek made contact with the gun, lifted his right elbow straight out and leaned forward slightly, ready to compensate for the kick when it came.

Frank checked the stance out, and then nodded. The boy was a natural mimic; he seemed to have spotted the essence of the position just by observing Frank earlier. That made it easier to teach him.

"Okay, load the gun."

Sherlock brought the gun down from his shoulder, pushed the lever that opened the breach, and inserted the red cartridge that Frank handed him. He resumed the stance, and pulled the gun in snuggly to his shoulder.

"Click the safety off, point the gun at that larch tree on the middle of the hill. I want you to aim carefully with your eye at a point about two meters from the top of the tree."

Sherlock asked "Is that point where you want the shot to hit? If it is, then I have to aim higher to compensate for the distance."

Frank smiled; the lad had caught on to the mathematics of trajectories very quickly. "Just aim where I said, Sherlock, and let's see if we notice where the shot actually hits. When you are ready, pull the trigger smoothly."

A moment of silence passed and then the gun went off.

"OH!"

"Yes, it does pack a bit of kick, doesn't it- which is why it is important to keep it firmly into your shoulder. Did it hurt?"

"No, it didn't hurt. It was BRILLIANT. Can I try again? This time, can you watch to see if I actually got anywhere near the target?" His eyes were wide with excitement.

"Okay, open the gun and eject the cartridge. Reload- this time you can try both barrels."

By the end of the second week, Sherlock was shooting clays like he'd been doing it for years. Frank was very pleased. Mycroft was due to come down from Oxford at the end of October for a Thursday half-day shoot; Frank was certain that he'd be able to convince him to take his brother out for his first attempt at live game.

"What do you like most about shooting, Sherlock?"

"The chemistry. Gunpowder explosions are _fun!"_

oOo

John was examining the third such body in a night- all victims of a close-range shotgun blast. When he had been in Afghanistan, his surgeon's skills were used to patch people up who had been shot- but every patient he'd treated who was a victim of gunshot, it was from a bullet, not the pellets of shot. While high velocity, high powered sniper weapons left their own trail of devastation, shotguns were an entirely different proposition. No one of the tiny pellets was as potent as a bullet, but given the number and the spread of wounds inflicted, a shotgun blast could be just as lethal.

The three men killed were all security guards at lock-up warehouses. Sherlock was pacing about the crime scene. They'd viewed the CCTV footage which showed two men bursting in and shooting the security guard at his desk, a good forty feet from the entrance. The two men were dressed in black from head to toe and unidentifiable. The shooter calmly picked up the ejected cartridge and then disappearing with his colleague into the warehouse. The same scenario had been played out at each of the three warehouses, separated by no more than five miles, and an hour between each attack.

Sherlock was pacing. Every so often, he'd stop and glance at the dead body. Finally, he asked John to remove the victim's uniform shirt. He crouched down and pulled out his pocket magnifier, examining the spread of wounds carefully.

Lestrade was watching the pair, whilst getting the details from Sergeant Donovan. "It's just like the others, guv. According to the warehouse manager, the guard has been working for only a month. Reliable, impeccable references, the CCTV shows him getting blasted the second he released the electronic lock on the door to let the thieves in. I don't get it. Why would they shoot their own inside man?"

The grey haired DI didn't answer, just strode over to Sherlock and John. "Come on, Sherlock; I need to know what's going on. Three in a row, all the same MO, but _nothing_ gets taken. Why is it happening?"

Sherlock stood. "You say nothing was taken, but in every case, you have only the warehouse manager's word for it. True?"

"Well, yes, of course. But why would they lie? I mean, if something was stolen, then it would be in their best interests to report it, so they could claim on insurance. In fact, that's one of the issues with this kind of theft. All too often, the warehouse operators chuck in a few extra things, claiming that they've gone missing when in fact they just want the extra insurance money."

"Lestrade, you're being an idiot. What's a theft, when it doesn't involve taking goods?"

Greg frowned. "You're talking in riddles, Sherlock. Just spit it out, if you've actually got something useful to contribute."

The brunet shot him a filthy look. "It's not theft; it's extortion. You are looking at this all wrong; think protection racket. These three warehouses that have been targeted are being shaken down. Maybe they didn't want to pay, maybe they thought by beefing up their security, they'd be able to refuse the attempt to extort money."

He let that sink in, as he bent back down over the body.

The DI sighed. "Well, that makes life even more complicated. At least with stolen goods, there's a chance to track where they turn up again, who's handled them and chase it back to the actual thieves. With extortion, none of the warehouse operators is going to say anything for fear of being targeted again. We're stuffed."

"Oh, I wouldn't say that." Abruptly, Sherlock stood up again. "I'm off to Barts. I need to see the three bodies side by side. And an example of the pellets pulled out of the wounds. Can you get this body transported there as quickly as possible?" He was already half way out the door by the time Lestrade said yes. John followed just in time to fling himself into the taxi that Sherlock had magically conjured up out of thin air.

"How do you do that, Sherlock? We're in the back of beyond in a run-down East End industrial estate and you find a cab."

"New app." Sherlock showed the doctor his phone- GetTaxi for Blackberry. "I called one here as soon as I saw the body, didn't think it would take me more than fifteen minutes. At this time of night, they are desperate for a good fare, and I've got an account with them. That, by the way, is also to deal with the fact that you are always complaining that I leave you to pay. When I'm on my way to a crime scene, this will save time. And being an account holder means that when they check the request, they see it's from me and that it comes with a guaranteed 20% tip to what's on the meter. Works every time."

When the three bodies were side by side on the tables at the morgue, Sherlock sent Molly off in pursuit of the evidence bags into which she had deposited the shot pellets she had removed in the course of the first autopsy. Then Lestrade joined them.

"I do hope you've got some way to figure this out, Sherlock. There's just nothing coming out of the warehouse owners- too scared, I think."

"With good reason." John was looking closely at the previous two victims, now lying on the table.

Sherlock paced. When Molly re-appeared, he grabbed the evidence bag and held it to the light. He smiled.

"Right. All three guards have been killed by someone using a sawn-off double barrelled shotgun- that much is clear from the CCTV. But, the pellet spread shows the gun to have a quite distinct character. Normally, a sawn-off has had up to fifty per cent of the barrel cut off, which loses the choke. That means the pellets spread out very quickly, limiting the range. But these guns have a choke, so not a 'sawn off' but more a made-to-order, with a full choke to ensure that they can used be at a reasonable distance."

Lestrade made a face. "Does it really matter what sort of gun?"

Sherlock glared at the DI. "Of course it matters! The second clue is in the shot. Most gangs using sawn-offs use cartridges with steel slugs rather than pellets- they're cheap and easy to obtain. Humans are bigger targets and not that fast, so pellets are actually inefficient. These pellets in the bodies are NOT cheap; it's birdshot used for water fowl, where no lead is allowed. Did you see from the CCTV footage? They are very careful to pick up their ejected cartridges- that's because the cartridge case would give something important away. Given the distance involved and the patterning in the wounds, I believe they are using Gamebore- that's a British manufacturer producing a three and a half inch steel cartridge, with a 42 gram load of 1 sized pellets. It's used for taking goose on the marshes."

Now he held up the evidence bag in front of Lestrade's face. "This is steel, not bismuth, so not the American-made Winchester Drylock. This is expensive- ten pounds or more per box. "

He consulted his phone. "You're looking for some people who have a legitimate reason for having this kind of gun and ammunition. A sawn-off can be used in fowling for shooting from a boat, not a blind. You are literally in amidst the landing geese, so a full length just gets in the way. Given the location of the warehouses in the East End, odds are that your villains are using this kind of weapon and ammunition on the waterfowl shooting grounds to the east- most likely on the Rivers Crouch and Blackwater in Essex. There are half a dozen syndicates working those areas."

Lestrade now looked puzzled. "Okay, so we have some place to look for leads, but there could be hundreds of people in those syndicates."

Sherlock rolled his eyes."Use your brain, detective inspector. All three of the dead bodies lying right in front of you are Eastern European in origin. Even if the CVs are a lie, you can't cover up the accent that well. So, someone involved in one of those shooting syndicates is going to have a business bringing in labour from Eastern Europe. Norfolk, Sussex and Essex agricultural harvests depend on these migrant workers. Alongside the legitimate employees, I'll bet the gang master is bringing in the occasional illegal- and setting them up as security guards. The CVs for the guards are obviously fakes- these people were planted by the gang so that they would pass them information about the warehouse companies and let them in when the time came. Do all three on one night, remove the only people who could link the killers to the gang, and we have motive for their death. Do all three in one night, so as to minimise the chance of the guards getting scared and talking. It's logical."

Lestrade looked perplexed. "So, you want me to get the names of the Essex marshes shooting syndicates, check them for anyone who has a gang master's license and …he's the one behind the warehouse jobs?"

"Yes, that much is obvious, Lestrade, isn't it? What part of the deductive logic has escaped your tiny mind?"

John smirked.

"And you got that from a single pellet of shot."

"Yes, of course. I do know something about gun powder, shot and shotguns, Lestrade."


	22. Chapter 22

**Periodic Tales **

**Chapter Twenty Two**

* * *

**Sulphur (Part three)**

_A Chinese text dated from 1270 AD, lists sulphur tipped sticks being sold in the markets of__ Hangzhou a__round the time of__Marco Polo's __visit. The first modern, self-igniting match was invented in 1805 by Jean Chancel in Paris. The head of the match consisted of a mixture of__ potassium chlorate, sulphur, sugar and rubber; it was ignited by dipping the tip into a small bottle filled with sulphuric acid. Modern "safety matches" remove the risk of self-ignition by separating the key ingredients, some of which are on the striking surface attached to the outside of the box._

* * *

Lestrade was waiting impatiently for Sherlock's reaction. For once, the consulting detective had been at the scene of the crime for a good ten minutes without uttering a word. He was not whirling about the place with his usual ferocity, trying to absorb everything he could set his eyes on. With good reason- this crime scene was just about the strangest in the DI's experience.

"Tell me again, Lestrade. This time, put it in the right order," the brusque baritone commanded.

Greg sighed. If Sherlock was asking for something to be repeated, that suggested he too was struggling.

"Two unidentified body parts – an arm without a hand, and a leg without a foot - were delivered to Mrs Williams two hours ago in a sealed container, vacuum wrapped in plastic, inside a plain insulated cardboard box. She's a widow in her late thirties raising three kids on her own; husband was in the army, wounded in Afghanistan, but returned there, serving half of another tour of duty before he was killed in action. She buried him three months ago and has no idea who could be horrible enough to send such a thing to her, nor any idea why."

John shifted uncomfortably. Sensing his discomfort, Lestrade moved on. "We traced the delivery company. The courier service had no idea what was inside. This is the address where they picked it up- from the reception area we've just come through to reach this room. There is not a stitch of trace in that reception area- as you saw for yourself. And no sign of the person who signed the paperwork either- a South Asian male, mid-thirties, average height, weight, dressed in a uniform. Spoke English like he was born here, but his family were likely Pakistani. The courier can't remember any badges on the guy- and the sign that was on the door when he picked up is now gone, along with all the other bits that made him think it was a normal office."

"Did you ask him what these 'bits' were? I need to know exactly." Sherlock's tone was peremptory.

Lestrade sighed. "Yeah, well, his memory isn't exactly forensically sound. He said there was a phone on a desk, a calendar and a photo on the wall, a chair, and a potted plant in the corner. Neat and tidy, but nothing out of the ordinary. And now- it's all gone; the reception is empty of everything he saw."

The DI continued in a resigned tone, "The courier said the pickup order came from "Acme Company" at this address- no such company has been registered at Companies House, so obviously a set-up, just to ensure the delivery was picked up. When we got in here, the blood is the only thing we found. I've sent a sample to the lab to check if it is from the body parts, but other than that we've got nothing to go on- apart from this weird room." His own frustration was evident in the tone of his voice.

The room was startling- a totally empty two meter cube with stainless steel floor, walls and ceiling, polished to gleaming perfection without a single finger print or footprint that had not been put there by the Forensic team. No windows, and only one door that closed with a hermetical seal. There were air vents in the ceiling, and one on each side of the room near to the floor. The Forensic team had tried everything in their field kit- and found nothing apart from the large puddle of blood.

"Lestrade, get out. Get everyone out of the room. I need to concentrate."

John made a face. Sherlock's social skills were seriously dysfunctional today- probably because of his frustration, but it was still too rude to be tolerated. "Sherlock…" there was an undercurrent of warning that he knew the consulting detective would pick up.

"You included, John." He didn't look up. His eyes were fixed on the blood, yet seemed unfocused- looking, but not really seeing it. John decided retreat was sensible, so he went out with the DI and the remaining three Crime Scene Examiners. He didn't know them- and thanked whatever gods were watching that it had not been Anderson and his crew today.

As he left the room, Sherlock said quietly, "Shut the door and turn off the light."

That made the doctor pause. He wasn't claustrophobic, but the thought of total darkness in a sealed room was not his idea of fun.

"…and keep silent out there; I can't have any distractions."

John rolled his eyes. _Whatever rocks your boat, Sherlock_. Once outside, he and Lestrade exchanged a concerned look, then the DI whispered, "How long should we give him?" John just shrugged.

In the dark, and in silence, Sherlock could now breathe. The scents of the room perplexed him, but with so many other people in the room, it had been impossible to identify what was bothering him. Some scents he could block out- John, with his combination of antiperspirant, shampoo and laundry detergent, overlying his own body odour. That Sherlock was familiar with- as he was with the same combination on Lestrade- different brands, different scents, but still very recognisable. The Forensic Team's blue suits masked some of their aromas, but the plastic itself was unbelievably distracting, both in terms of scent and the rustling sound that he hated so much. It was like trying to hear the faintest whisper in a room where everyone else was shouting. Once they were gone, he could concentrate on the whisper.

_What are you trying to tell me?_ By closing off sight, and eliminating sound, he hoped to understand what it was that he had missed so far. He stood absolutely still, slowed his breathing, and tried to block out the sound of his own blood whooshing in his arteries and veins, the beat of his own heart.

The blood was a problem- the room reeked of it. He tried to eliminate it. Chemical notations came into his mind palace. Plasma, with the red erythrocytes, white leukocytes- the lymphocytes, monocytes, eosinophils, basophils, granulocytes, thrombocytes. Then there were the fat globules, and the carbohydrates, proteins and hormones, as well as the odourless oxygen, nitrogen and carbon dioxide. He understood the chemistry that was driving the blood's scent. _Break it down into chemical components, then dismiss it_.

What was left? His own scent could be eliminated. Familiarity bred contempt- ignoring it came naturally. His sense of smell then became fixed on the stainless steel and its metallic tang. _No, that wasn't significant._ He'd been smelling the metal since the moment they opened the door. It had to be something else.

He licked his fingers and then spread the saliva on his cheek, where it cooled, reacting to a flow of air in the room- yes, definitely driven by machinery, but not the usual sort of circulation. This was laminar, unidirectional, and designed to keep the air moving in a constant stream towards the filters near the floor.

_Stupid!_ He suddenly realised why the scents of the others disappeared from the room so quickly. In a way, it was the absence of scents that had triggered his unconscious mind. He bent down and found the air outlet with his fingers, then crouched so his nose was scarcely an inch away from it.

_There- something elemental. _ He caught the faintest whiff, so he drew in a deep breath through his nose. _Yes! Sulphur dioxide, caught in the filters!_

He smiled in the darkness. That told him more about the murder than anything else.

Sherlock felt his way along the wall until he reached the door and opened it, blinking in the sudden light. When he could see Lestrade and John clearly again, he said, "I've figured it out. Someone's been playing with matches."

The look of confusion on Lestrade's face was mirrored on John's. "Care to translate that, Sherlock?"

The brunet threw them both one of his smug smiles. "I meant it, Lestrade, literally- the murderer used burning matches to try to throw us off the scent, but it can't fool me. Humans are hardwired to react to sulphur compound smells, because they play such a large role in decomposition. Our nose detects it, fixates on it- and it keeps our nasal receptors occupied. Someone burned a whole book of matches in this room to disguise the decomp odour. Get onto the morgue and ask the coroner to test for ice crystal damage of the red corpuscles; he'll find that those body parts will show signs of being frozen and then thawed. And the blood on the floor will be from the same source. Check the DNA against those of the widow's children. I believe there will be familial markers that show the body parts are from their father."

Lestrade looked even more confused. "Sherlock, the guy was buried three months ago."

Sherlock was now in full flow. "You'll need to organise an exhumation. Whoever was buried by the widow wasn't her husband. I'm going to call Mycroft- I think we've been sent a message about someone who was working undercover amongst the Taliban in Afghanistan."

Now it was John's turn. "But, Sherlock, why on earth did you say the body parts had been frozen?"

"How else to get them from Afghanistan to the UK? They may well have killed him quite a while ago. Mycroft will be able to find out when his last intelligence report was filed. For all we know, the Taliban could have blown his cover ages ago, killed him, frozen the body and kept sending bogus information. When they thawed the blood to pour it on the floor and boxed up the body parts, it must have smelled of decomposition, so they tried to mask it by burning matches. A scent that strong remains in the filters for quite a while when the particles are removed from the circulating air."

"And that's the reason why we were led here. This is a clean room. I'll bet it's one used by some branch of the British security services to handle substances that they aren't too sure about. For all we know, Mr Williams, if that is his real name, was someone who used this very room. That would be poetic justice in the eyes of the Taliban."

Whatever doubts the John might have had about the tenuous connections drawn by Sherlock were dispelled when he saw several black government cars pulling up outside the reception door. Nor was he surprised when Mycroft himself got out and came to into the reception.

"You're slipping, brother." Sherlock was almost gleeful. "We've been here for at least an hour and you didn't notice?"

Mycroft frowned. "This facility was de-commissioned seventeen months ago. It's no longer monitored."

"Tell that to the Taliban. They've delivered a rather nasty message and you'd better check the intel you've been getting from your undercover agent. I suspect a disinformation campaign."

The minor official in the British Government gave a rueful smile. "How do you figure all this out?"

The brunet smirked. "Remember telling me not to play with matches? Lucky for you, I ignored you."

"And you wonder why I keep asking you to work on cases for me, Sherlock? Perhaps with you on our side, this wouldn't have happened."

As he swept out, Sherlock said over his shoulder. "I will continue to ignore that sort of request, Mycroft. It's better for both of us that I do continue to play with matches. Come on, John."

oOo

"Good afternoon. I'm Robert McGarry, and I'm the Chemistry master. You seven are new boys, joining the college in the summer term. Over the next seventy five minutes, it's my job to figure out what to do with you lot. You've all passed your Chemistry GCSE, and declared your intention to study for the A Level. I have to decide whether to let you join the rest of the class who started in the autumn term in the hope you'll catch up or to hold you back until next September. And I have to decide which teacher you'll get." The grey haired teacher looked at the six boys, most of whom were 16 or 17 years old. The kid sitting at the back desk clearly wasn't that old. He guessed that the weedy looking boy must be Holmes, who'd taken his GSCEs early at 13, getting five As and one B.

"There are three chemistry teachers here at Harrow. Me, Mr Alcott and Mr Samson." McGarry consulted the register of names. "Mr Fielding, if there are six of you and three teachers, how do you recommend I allocate you?"

Les Fielding gulped, but then spoke tentatively, "Two each sir?

McGarry sighed. "yes, but on what _basis_? Draw lots, random- how?"

Fielding thought about it, and replied, "what about alphabetically? That would be fairest."

The chemistry master frowned. "What has _fairness_ have to do with it? This school prides itself on delivering student-centred teaching. Mr Patel, what data do you need to know to be able to make an educated guess about how that can be achieved with you six?"

The Asian youth was quicker than Fielding. "GCSE results could be used to separate the six, sir. Those with the best scores could probably catch up, those with the worst should be held back, and you could allocate them to teachers according to which class is most similar in test results profile."

He made a show of considering the idea. "True, but that's not even half the story, is it? You need to know something more about the teachers than just test score profile. So, let me tell you- Alcott is the chemistry teacher whose students consistently score the highest A Level results, while Samson is always recognised as the most popular, so the boys in his class swear he's the best." He consulted the register again, "…Mr Forbes, what can you conclude about _me_ from those statements?"

The broad-shouldered lad blurted out "that you are neither as popular nor as successful as the other two."

"Ouch."

The boy went bright pink as he realised that he had just insulted the master. Forbes was a rugby player; McGarry knew that from the excitement of the sports master, who claimed the new pupil should help the college team improve its performance.

He was quick to save the boy from embarrassment. "Actually, that is a fair assessment, according to the criteria of test scores and popularity. So, gentlemen, if this was a democracy, would anyone here vote to join my class?"

One hand went up immediately.

"Mr Holmes…why?"

"Because you are a chemist, sir, and that matters more than teachers who teach to a test or who try to be popular."

McGarry raised an eyebrow. "How did you arrive at such a conclusion?"

Sherlock did not hesitate. "Your labcoat. I've seen the other two teachers in the corridor. They wear theirs to protect their jackets, and take them off as soon as they leave the classroom. You wear yours all the time because it's what you prefer to wear. And just look at it- stains from working with chemicals; that purple is unique- the result of a Molisch's test for the presence of carbohydrates, where the molecule is dehydrated by sulphuric acid to produce an aldehyde which condenses with two molecules of phenol resulting in that particular shade of purple. You don't _talk_ about chemistry; you do it. I'd rather be taught by a chemist than by a teacher."

This came out at blinding speed, and some of the other boys turned around in their desks to take a closer look at him. Someone muttered, "what a geek."

McGarry intervened. "That's quite…observant of you, Holmes. Too bad this isn't a democracy and that boys don't get to decide for themselves who will teach them." He stood up and started down the aisle between the two rows of desks, handing out a blank exercise book to each of the six.

"Right now it's time for me to learn something about you- other than your test results. I want you to select a chemical reaction- _any_ chemical reaction with which you are familiar and personally interested. And then I want you to write for a solid hour about it. If you don't think you can write that much about something that comes to mind, then keep thinking until you find one that will keep you going longer. I am interested in the depth and breadth of your knowledge, gentlemen. So, the clock has started ticking."

He always enjoyed this part. Pupils were rarely if ever given the chance to select what they wrote about; so much of teaching seemed designed to get them to remember things by rote and then regurgitate the chemical formulae and processes on demand. Now given freedom to write about anything, he watched as confused and startled looks were exchanged between the boys. Only one started immediately. Holmes. _How did I know that was likely? _

An hour later, Holmes was still writing, when the other five had finished some time before. "Thank you, gentlemen. There will be a note on my door tomorrow morning with your chemistry teacher indicated. Now off you go, back to class."

He taught his own lab class until six pm, then went home, carrying the six scripts. Before supper at seven, he'd read the first four. Three were simply re-hashing one of the GSCE questions about making hydrogen sulphide from hydrochloric acid and magnesium, and its relationship to the origins of biological life. _Right, the best two of these go to Alcott._ The third from Fielding was quite tentative, full of grammar mistakes, but at least there was a glimmer of an argument that he'd remembered from his GCSE exam. He allocated this boy to Samson. With encouragement from a popular teacher, he'd probably scrape through.

McGarry didn't even bother to do more than skim Forbes. It was a hopeless attempt to get at nuclear reactions with uranium. He had only a dim understanding of how to balance equations, and his handwriting was abysmal. Alcott's class of high achievers would simply eat him alive, so he assigned him to Samson. _Yes, he'll do well enough with Samson._

That left Patel and Holmes to him. McGarry lived alone in his small terraced house in Harrow. His wife had died three years ago, so he was now into frozen meals and convenience foods, which he consumed as he flipped through the Asian boy's exercise book. He remembered the boy had finished early, but seemed content with his answer. His choice was clever- not one but three different versions of desalination of sea water- hydration, distillation and electrolysis. He clearly understood the role of ions, and of the three processes, even if his chemical formulae were a little basic. He described the experimental process well, realising the need to identify the salt concentration in the sea water first. He had potential.

After a brief break to watch the television news, he poured himself a brandy and opened the last exercise book.

_16KClO3 + 3P4S3 - 6P2O5 + 16KCl + 9SO2_

_So many chemistry experiments start by someone lighting a Bunsen burner by striking a match. It's surprising, however, how few people stop to think about how the match was invented and the chemical problems it presented. Even if you ask a chemist, they will just dismiss it as a basic combustion reaction and explain its exothermic character. _

_If it was so simple, then why did it take SO long to invent a viable match? _

Quirky choice, possibly interesting. At least the formula balanced. He skimmed down the first page.

_The modern safety match head contains sulphur and oxidising agents (usually potassium chlorate) with powdered glass, colourants, fillers and a binder made of glue (which also acts as a fuel) and starch. The striking surface consists of powdered glass (sometimes sand –silica), together with red phosphorus, binder and filler. When you strike a safety match, the glass-on-glass friction generates heat, converting a small amount of red phosphorus to white phosphorus vapour, which spontaneously ignites. But this would not be enough to produce a usable flame- it would burn out too quickly if it relied solely on oxygen from the air, so , the white phosphorus decomposes the potassium chlorate and liberates more oxygen, which means the temperature rises to the point where the sulphur starts to burn, in turn reaching the temperature needed to ignite the wood of the match._

There followed the exact chemical formulae needed to explain each step. And, as a bonus, what would happen to the formula if the potassium chlorate wasn't there. Then there followed a bit of history.

_One clue is in the word "match" which is derived from the old French word for candle wick (meche); in fact, for a long time the concept was linked to cord- the fuse used in matchlock guns, for example, is cord, not wood. Despite the Chinese "inventing" wood tipped with sulphur as long ago as the 13__th__ century, no one in Europe was able to manufacture a workable cheap version until the mid to late 19__th__ century._

There followed a detailed chemical explanation of the volatility of white phosphorus, and how toxic it was to make matches using the material. A rather macabre note was added in the margin about how in the 19th century one method of committing suicide was to eat a box of matches. The essay went on to explain how chemists struggled to contain the combustion and its lethal side effects led to the discovery in 1850 of a new allotrope- red phosphorus, which was much safer. McGarry found himself enjoying the story. It was an intriguing blend of history, practical difficulties of manufacturing and pure chemistry. At every point the chemical notation was immaculate.

He took a sip of his brandy and turned the page. His eyes widened. He leafed through the next four pages of dense mathematical calculations, before returned to the start of the equations.

_To understand the chemical reactions involved, it is important to comprehend the underlying physics involved in the movement of the atomic particles through the process. The kinetic and exothermic energies involved at each step need careful explanation._

No wonder Holmes was still writing when McGarry had called time. He tried to recall when at university he'd started using higher level mathematics to calculate the underlying physics of his experiments. A quick squint through the pages made him realise that Holmes was as comfortable with calculus and quadratic equations as he was at chemical notation. _He's only thirteen; who the hell has been teaching this boy?_

The next day McGarry introduced his second year A level class of 17 year olds to a new student, and paired him up with the dimmest of the cohort. Today's lab experiment was a demonstration of flame colours of different elements of the periodic table, which involved salt suspensions being sprayed onto an open flame inside a fume hood. The reactions which would be observed spectrographically through a diffraction grating. Boys would be required to write up the findings including calculations which explained the phenomenon in terms of excited electrons.

"Mr Holmes. Strike the match please and light the Bunsen burner. Take ten minutes to explain to the class something about the process that all too often we chemists take for granted."


	23. Chapter 23

**Periodic Tales Chapter Twenty Three**

**Author's Note: **This one is for SailOnSilverGirl to wish her some good cheer. Hospital visits are never fun, even if they are routine. This is some escapism, based on her prompt.

* * *

**Rhodium (Part One)**

**Rh 45 102.905**

_A silver-white chemically inert transition metal that is part of the platinum group. With only a single isotope, it is one of the rarest and most valuable precious metals. Its rarity affects its price and therefore its commercial applications._

* * *

John shifted his weight a little from his left leg. It had gone numb.

"Don't fidget, John. They will show up."

The doctor sighed. They had been waiting for almost four hours in the cold. The wheelhouse of the boat protected them from the wind, but it wasn't heated. The wooden deck beneath him moved gently; the incoming tide up the Thames was beginning to reach the St Katharine's Dock marina at last.

Sherlock had taken him aboard the _Havengore_ at 11pm. Unbeknownst to its current owners, a corporate hospitality company, the consulting detective had decided it was moored at the perfect vantage point to observe discretely the comings and goings of boats into the three separate mooring areas of the marina. He had picked the lock with consummate ease, and commandeered the bridge. "It's perfect, John. No vessel can get in or out of the marina without passing right in front of us."

All around them, the power launches and sailing yachts of the City's wealthiest seafarers bobbed in the swelling waters. The water levels in the dock were carefully regulated; when the tide retreated, lock gates kept the depth of the marina artificially high.

The case was most unusual, brought to Sherlock by a city investment analyst from the London Metal Exchange.. Aside from Michael Shaunnesey's day job regulating the sale of over 80% of the world's non-ferrous metal trading, he followed the much less transparent market of precious metals- platinum, palladium and rhodium, in particular. The last two of these were traded in such small volumes that they never made it onto any of the big market boards. But, you could get prices from suppliers. He had developed a computer price tracking programme that detected a recent price manipulation- but couldn't prove a thing. He parked his Boxster Porsche in front of 221b, climbed the stairs and recounted a dark tale of market misdeeds. He built a persuasive case, but, no one in the City Police or the market authorities understood enough about what was happening to know what to do about it.

"Trouble is, it's fiendishly difficult to figure it out." He showed Sherlock a complicated chart that tracked the price of rhodium per ounce around the world's specialist providers over the past five months. "I can see it, but I don't know what is causing it. The only thing that could be affecting it like this is the sudden appearance, like magic, of a source of rhodium that no one knows anything about. The price is being artificially boosted, and then when it reaches a real crunch point, the criminals do some profit taking by dumping a consignment of about a quarter tonne. And that's impossible. Every mine is known, every production quota is scrutinised in detail. There is just such demand for Rhodium worldwide that we'd know if the stuff was legal."

"I'm at wits end, Mr Holmes. No one seems able to do anything about it. All I am asking you to do is think about the problem. And, if you come up with some ideas, then maybe we can get the police interested. Given your track record with the police, they just might listen to you, whereas they just think I'm some computer nerd with a conspiracy theory."

The consulting detective had been listening quietly, with his eyes half closed. For a moment, John thought he was going to do his usual "boring" routine and dismiss the prospective client as being just what he described himself as - a geek with a nutty idea.

"What's the current price of Rhodium?"

"$5,321 an ounce." Shaunnesey's reply stunned John.

Sherlock's eyes opened. "That's nearly 43 million dollars' worth, if they are able to shift a quarter of a metric tonne."

"Yes- you see my point, Mr Holmes. I just can't prove it. It's pure speculation, in more ways than one."

Silence fell in the room, as Sherlock considered the problem. He brought his hands up under his chin in a prayer position and half closed his eyes again. Shaunnesey cast a puzzled glance at John, who decided that now was the time to offer the client a cup of coffee.

The City analyst followed him into the kitchen, where his expression showed his surprise at the haphazard collection of laboratory equipment strewn across the table. "Um, is he always like this? Do you think he will take the case?"

John gave him a reassuring smile. "He already has. He would have dismissed you instantly if he didn't want to get involved. He's…thinking. That's what you asked him to do, so he's doing it."

When the two went back into the living room, John just put the cup of black coffee into Sherlock's outstretched hand. A moment later his eyes opened.

"Well, Mr Shaunnesey, this is an interesting one. Initial thoughts – and probably that is as far as the authorities got, given their limited brains- were that this is a scam. But your evidence suggests repeated success, and to do that means the criminals actually have to deliver the goods. You can fool suppliers desperate for the metal into parting with cash once, but if the Rhodium doesn't turn up, they are unlikely to buy again."

He took a sip of his coffee. His interest showed in the baritone. "So, someone is sourcing, moving and delivering a cargo that weighs just over five hundred pounds- and reaping huge rewards. Yes, I will take this case. It is a challenge. That sort of volume is quite easy to move around unseen by the authorities."

Michael Shaunnesey relaxed the tension in his shoulders and took a long sip of the coffee. "I can see I've come to the right man. You _know_ about Rhodium."

"Oh yes."

John frowned, and looked at the two men in annoyance. "Well, I don't, so just fill me in, please."

Sherlock smirked. "It's a case of business economics, John. If you are going to smuggle a metal, then make it one that is very high priced. Gold is just too _plentiful_, despite its reputation. And its price is volatile, reflecting the state of equity and money markets. So, it's currently selling at under $1,000 an ounce. Over the past decade, Rhodium has been worth between five to eight times _more_ than gold, four hundred and fifty times more than silver. Rhodium is _rare_- and it isn't an investment metal, its users are far more consistent in their demand. The volume of metal involved in a quarter tonne of Rhodium would fit comfortably into the back of a white van. That makes moving it …more interesting."

He now focussed his attention on Shaunnesey. "Why do you think that the smuggling is happening here in London?"

The analyst put his coffee cup down, and pulled up the print outs again. "The price data is timed- so I can track it around clock, to find the best price. The price peaks are always timed when the London markets open. That's what made me suspicious in the first place. So, well, if the statistics are accurate, then it's based here."

Sherlock considered for a moment, then nodded. "The balance of probabilities says you are correct, Mr Shaunnesey. The inexorable rise in the price over the past decade has been driven mostly by Chinese demand, but their preferred sources are in South Africa rather than Russia."

The analyst nodded. "Yes, I can see you've been watching the news, Mr Holmes, so you know about the Bushveld mines labour disputes that are stopping platinum production."

Sherlock gave a sharp nod. "Every day the strike continues, prices are rising- which creates an unprecedented opportunity for anyone sitting on a supply of Russian rhodium. But it won't last, the South African government may have botched the first round by taking too heavy a hand with the strikers, but the multinational mining companies will give in and raise wages. It's only a matter of time. It is logical to assume…."

Sherlock stopped and looked away. His eyes were unfocussed, his expression blank for a moment. John looked at him with concern. "Sherlock, are you alright?"

"OH!" The consulting detective's eyes snapped wide open. "Mr Shaunnesey, we will have to move fast. I believe a consignment may already have been sold- just not yet reported on your statistics. The criminals will not want to delay in delivering- because it's going to be a whopper- probably as much as half a tonne. The risk of moving that valuable a cargo on roads from north eastern Siberia where it's mined– challenging- and it would take _days_ to get from there to here. And that would run too many risks that the South African labour dispute will get solved and the value of the cargo suddenly plummet in value. So, a plane would be quicker, but again, the weight would be interesting, so not a light aircraft, and customs officials at proper cargo airports are getting harder to bribe- too high risk… so I think they are moving this by sea. Not by container, no- that takes even longer than by truck. Try a superyacht- one of the big power boats that come in and out of the Docklands area on a regular basis- quite a few are owned by Russian oligarchs. John, we need to head to East London." This stream of consciousness was uttered at a speed that left both the doctor and the City analyst reeling.

So it was that they'd spent the afternoon traipsing from one marina office to another, tracking down Russian-owned motorised yachts. Any that were already in port were scrutinised in terms of their documentation to see their recent comings and goings. With six marinas downstream of Tower Bridge to investigate, they'd split up after the first one, once John knew what he was supposed to be looking for. He kept Sherlock informed by text. Through hard slog and sweat, they'd narrowed it down to two possible boats moored at St Katharine's dock. One vessel, the _Vlad_, was already moored, having arrived there in the afternoon. The marina CCTV showed no signs of anything other than a single man leaving with a briefcase. The other empty slip was awaiting an arrival that had been booked for the morning tide.

In the wheelhouse of the _Havengore_, the doctor yawned. Waiting all night to see if anyone showed up to remove a half tonne cargo from the _Vlad_ was about as exciting as watching paint dry.

"Bored, John?"

"And you're not?"

"Of course not; I am patience personified when working on a case."

"Why's this stuff worth so much? It doesn't make sense. It's not like it's gold."

"Simple market forces combined with chemistry. Rhodium is rare and it is in demand. Only 25 tonnes a year is mined, and 80% of that goes into catalytic converters for cars, where the Rhodium is used to convert the pollutant nitrogen oxide into harmless emissions. As demand for cars goes up and China starts trying to tackle its air pollution problem, then it is inevitable that the price of Rhodium will keep going up. _Every_ legitimate supplier wants more. So, when half of 1% of the world's annual supply is available under the radar, the private auction price will go sky-high. "

As the night sky turned into dawn's pinkish grey, the doctor shifted his weight again.

"John, if your leg is bothering you that much, sit down in the captain's chair."

He grimaced, but complied.

"It's appropriate, _Captain_ Watson. Did you ever consider the navy instead of the army?"

"Nope- I get seasick."

Sherlock took his eyes away from the binoculars in surprise. "Really? _Mal de mare?_ You surprise me, John; I would not have thought that of you."

The doctor shook his head. "It's an inner ear thing. Just don't like having a shifting ground under my feet."

"Hmm…well, it won't be much longer. If the owners of the _Vlad_ had secreted a half tonne of metal on board, they certainly haven't been in a hurry to shift it tonight, and I would have thought they would try to offload such an incriminating cargo in hurry. So attention switches to the second boat which is due in soon."

The airwave radio sitting on the dashboard next to Sherlock crackled into life. "MPU control Wapping- target two has passed the Thames Barrier. ETA St Katharine's twelve minutes."

"Battlestations, John." He smirked. The Met's Marine Police Unit had been alerted by Sherlock, and were discretely monitoring the progress up the Thames of the second Russian registered yacht- a 40 metre Sunseeker, fully kitted for blue water global sailing, last recorded port of call in Russia was Murmansk. Owned by an oligarch with commercial interests in the Eastern Siberian peninsula, up at the Arctic Circle, the vessel was called The_ Tsarskaya Okhota_.

"Right on time." Sherlock's grin was almost feral. Warning lights began to flash, automatic gates dropping down to stop early morning traffic on St Katharine's Way alongside which the _Havengore_ was moored. Within moments, the marina lock gates were swinging open, and a sleek white yacht began to move slowly through the narrow opening.

"Yes, John, our ship has come in."

John looked through the binoculars, trying to see what made Sherlock so positive. "How can you be sure?"

"Weight, John. Look at how low in the water she is. Carrying more cargo than normal, a half tonne by my estimation." He switched on the airwave radio and notified the MPU. "That's your target, Wapping. Notify all units; search the cargo and crew."

Once the mooring ropes were tied off by a crewman, the rest of the scenario played out as Sherlock planned. Uniformed officers swarmed aboard and a search commenced. Out on the quayside now, Sherlock and John waited for confirmation. One officer emerged on the sunseeker's deck and raised a thumb upwards, bringing a smile to the brunet's face, before he turned and started to stride away.

"Let's stop in at the Tower Hotel, John. You deserve a hearty breakfast after a cold night."

The hotel restaurant had a stunning view of Tower Bridge to the southwest, but Sherlock chose a table that had a bird's eye view eastwards of the St Katharine's dock marina. As he tucked into his bacon and eggs, John watched Sherlock pick at a piece of toast, his eyes on the sleek boats. The doctor grinned.

"I might not like the sea much, but your brother once told me that you wanted to be a pirate when you were little."

That provoked a soft chuckle. "Smuggling has always been a feature of English history, John. But, these days, the smart money isn't on pieces of eight, there's more money to be made on ingots of Rhodium."

oOo

45-1+53+6+1+18+48-6

67+3-53+109-22-53+99

53+16

18-86-7

3+18

The strange sequence of numbers was written in bold black magic marker on a flip chart sized sheet of paper. Even more bizarrely, the sheet was hanging off the antlers of the deer head mounted ten feet up on the wall of the Great Hall. Richard Holmes knew it was not there when he had passed through the room just fifteen minutes before, on his way to meet Doctor Francoise Derrand, who just happened to be from the Haute Autorité de Santé, the French National Authority for Health responsible for clinical approval of drugs to be used in the country's health services. Derrand was an important man, one whose decisions about drugs could alter the fortunes of Holmes' many pharmaceutical interests overnight, should he be favourably impressed.

Now with his guest in tow, he was presented with the unexpected vandalism. An embarrassed silence ensued.

"Is this some strange English custom to welcome your house guests, _Monsieur_ Holmes?"

The tall man put a smile on his face as he turned to the Frenchman. "No, I can assure you it's not that. It's just my younger son's idea of a prank. I will be _seeing_ to him about it shortly. Just ignore it- he's of that age- thirteen and all about attention-seeking. You know how it is with youngsters these days."

The Frenchman smiled. "Of course. Only my nephew of that age is more interested in his computer games, football and music than some… mysterious code. So, your son is mathematically gifted?"

Richard Holmes seethed inside as he ensured that an indulgent smile remained on his face. "No. He's just got a sense of humour that's a bit…odd- just like he is. Now my elder son, Mycroft, is completely different. He's at Oxford now and attracting all the _right_ sort of attention. He's quite brilliant. Fluent in French, of course; as you know, my wife was half French."

As he steered Derrand through the oak door into the drawing room, Holmes pressed the button that would alert the butler to bring in tea. "I am so very pleased that your wife has been able to join us. My chauffeur is already on his way to pick her up from the airport and get her here in time for drinks before dinner. First, we will have a cup of tea, while the staff will ensure your things are taken to your room. After tea, when you've had a chance to freshen up, then we can get down to some business."

After the butler arrived with the tea and served the two men, Richard followed him to the door. Once on the other side, he said very quietly through clenched teeth "Wilson, how the _hell_ did Sherlock manage to get that…_thing_ up on the wall? Get it down immediately and take it into my office. When Mr Derrand is upstairs after tea, I want you to escort the idiot down into my office, and make sure he stays in there until I arrive."

He went back into the drawing room and set about charming the Frenchman. A large contract was at stake, and he wasn't about to get side-tracked by the distraction.

Once his guest was safely upstairs, Richard went into his office, throwing open the door without warning. He caught Sherlock sitting in the chair behind the desk. Richard's laptop was open and on. The older man smiled, mirthlessly.

"Trying to hack in, are you? Good luck. I'm not the idiot in this family." He reached into his pocket and dangled a fob- it generated a random alphanumeric code on a daily basis, synchronised every morning as the password. "Get out of that chair _now._" It was delivered in a quiet voice that nonetheless screamed with menace. Sherlock moved out of the chair, keeping the desk between him and his father.

The tall man sat down in the vacated chair and gestured angrily at the torn poster lying on the desk. "What do you call _this_, Sherlock?"

The thirteen year old did not flinch at the malice in his father's tone. "How long did it take you to figure it out?" The question was uttered in a cheeky nonchalance, as if he was not at all overawed by his father.

Holmes just sneered. "About ten seconds to realise that your unnatural obsession means that 43 is Rhodium. Thereafter it was simple. Fortunately for you, my guest is a medical clinician by training and not a chemist, so your use of the periodic table was totally wasted on him." He was watching Sherlock, who had started to feel the heat in his father's gaze. His bravado was beginning to evaporate under its intensity.

"Sit down. At any moment your anxiety is going to start making you fidget and you know how I hate the physical manifestations of your defect."

Sherlock glowered at him, but did grab one of the hard backed chairs by the window and positioned it a safe distance away from the desk.

His father continued. "Before you make accusations like the one on that sheet, it's wise to think through the consequences. Did no one ever tell you that slandering people is dangerous?"

Sherlock's fear of his father collided with his self-righteous belief in his own veracity, and truth won over caution. "It's not a lie; _YOU _are the liar."

"And what evidence does that feeble brain of yours care to offer for such an accusation?"

"Apart from the lies you told mummy about your adultery, I know you are suppressing the report on your drug- the one designed to fix cardiac arrhythmia; the evidence says it interacts fatally with other drugs likely to be in use by heart patients. But you're not telling anyone that- including this man from France, who might buy it."

Richard's face flushed. "How do you come up with such _drivel_, boy?"

"It's in the report sitting in the second drawer down of your desk. I read it last night."

"You've come into a part of the house that is explicitly forbidden to you. Picked the door lock. Read something you can't possibly understand and come to a very wrong conclusion. You're an idiot, Sherlock, and becoming a danger not only to yourself but now to me. This _stupidity_, this _provocation_ has got to stop, boy. I won't have you interfering in my business activity. You're certainly not worth it. I will send you away. Don't for a moment think you can stop me."

"I can stay here. It's my home too. Mycroft says I have a right to be here." His nervousness was betrayed in his voice, which seemed to have gone squeaky.

Holmes just laughed. "Seen your brother lately then, have you? He's in Central America, Sherlock; he's been there for months and he's unavailable to help you now." He stood up and started to walk around the desk. Sherlock had only seconds to decide whether to take what he knew was coming- a physical manifestation of his father's anger- or to flee. He was half way out of his chair when there was a knock on the door. He tore over to it and threw it open to reveal a startled butler.

"Sir, Mrs Derrand's car has arrived. Do you want to greet her personally or shall I get Mrs Walters to take her upstairs?"

Richard Holmes simply pushed Sherlock aside and walked through the door. "Don't think, boy, that you have been saved by this timely intervention. Postponed, yes; forgotten, never."

Less than an hour later, Sherlock was eavesdropping on the back stairs, not more than three meters around the corner from the Derrands' bedroom. They'd been allocated his mother's old room and he was a master at unseen loitering with intent, after years of overhearing his parents arguing about him.

Unbeknownst to the pair, like his brother, Sherlock spoke French. Within seconds, he'd figured out that "Michelle Derrand" was in fact, not his wife at all, but his mistress, who was masquerading as the wife. His real wife was back at home in Paris, oblivious to his plans for a dirty weekend at the expense of the Englishman. The two were laughing at his father for having been taken in by their act. Francois was equally derisory about the idea that a bit of good food at an English country house could influence him in any way when it came to making pharmaceutical choices.

Later after dinner, Michelle came up to the bedroom to get a sweater. As she pulled the black angora cardigan from her case, she spotted a piece of paper lying neatly on her pillow. Confused, she took it downstairs to the library where she found Francois and Richard enjoying a brandy.

She handed her husband the note. "What does it mean, mon cher?"

Francois scanned it, and frowned. "Richard, I believe your son is being mischievous. Do translate for us, please." He handed over the sheet, upon which the following numbers were written:

90+6-92+30

18+63-92

99-66-70+92+3-53+52+45-1+68+16

Holmes read it slowly, working through it carefully. His face must have betrayed something of his reaction to the message, because Francois caught his discomfort.

"What does it say?"

Holmes tossed it aside. "I don't think you want to hear the demented ideas of a thirteen year old, really, I must apologise for the boy's intrusion, Madam- it was unforgiveable."

Michelle looked intrigued. "I would like to know what it says, Mr Holmes. Please."

Francois Derrand decided that he enjoyed the man's discomfort. He'd been acting the lord of the manor all evening, irritating the Frenchman with his airs of superiority. "I insist, Monsieur. Honesty is the best policy, as you British like to say. So tell us what it says." There was an edge to his tone, one that Holmes picked up on instantly.

"I prefer not to do so, if you don't mind."

"But, I do mind. Think of this as a little test, Holmes. Transparency is important."

There was something in the Frenchman's manner that made Holmes realise he'd already lost the battle- and that the contract was already out of reach. That made him think.

"Very well, as you insist, the message is based on the elements of the periodic table, which can be substituted for the letters of the alphabet. It says, "They are adulterers."

There was a shocked silence.

"Madam, or shall I call you mademoiselle? I don't suppose Monsieur Derrand would like his real wife to know of your liaison this evening. By all means, enjoy yourselves tonight as my guest. I am a man of the world and respect your right to privacy. Although I expect your wife would be less tolerant should she come to hear about this. And if such a scandal were to become public knowledge? Well, I can imagine her brother, the Minister for Health, would take a dim view of it all, I am sure. So, I look forward to the negotiations about our supplies being approved by the Haute Autorité de Santé." He smiled at the stunned pair. _Thank you, Sherlock._

Later that night, Richard poured himself a brandy. Despite his ability to turn the situation to his advantage, he was under no illusions. He sat down at the desk, and took out a sheet of correspondence paper.

_My dear Mycroft, _

_I am writing to inform you that our "agreement" regarding your brother is at an end. Tonight he seriously jeopardised a crucial business relationship by indulging in outrageous behaviour. Although I have resurrected the situation, I can no longer tolerate the arrangement of sharing my home with him. _

_Either you move Sherlock elsewhere or I will do it myself. I need the London townhouse for business purposes, and I need to know that my guests will not be harassed or embarrassed if they visit my country home. It's time, Mycroft that you stopped indulging him. He needs firm discipline. You are not here and cannot do so from a distance. Send him away to a school that can deal with his special needs, and keep him locked away from the sight of those who need to respect this family. If you leave him here, then I will be the one to make the decision about where he goes. You have one month to make alternative arrangements. I am copying this letter to our respective solicitors. _

_I remain,_

_your loving father _

* * *

**Author's note**: I am indebted to whitchry9 for the idea of the periodic table as code. See if you can translate Sherlock's poster!


	24. Chapter 24

**Periodic Tales**

**Chapter Twenty Four**

* * *

**Rhodium (Part Two)**

_Discovered in 1803, Rhodium is named for the rose colour of one of its chlorine compounds. Rhodium is a "noble metal"; that is, it is inert to corrosion and most aggressive chemicals. White gold is often plated with a thin Rhodium layer to improve its appearance and sterling silver is often plated with Rhodium to improve its resistance to tarnish. _

* * *

John followed Sherlock toward the front door, which stood wide open. A traditional semi-detached in one of London's northern suburbs, the two storey house had been built sometime before the last war, and withstood the blitz. A few new low-rise apartment blocks on the same street stood as mute testimony for those houses not so lucky to escape the bombs. Now this area of Golders Green had been colonised by wealthy professionals.

The hall lights were on, and the constable standing on the black and white tiled floor directed them into the living room. Sherlock swept in and took in the scene, with John close on his heels. The doctor saw the immaculately detailed room, the tell-tale signs of someone who read all the interior design magazines- tasteful, expensive and oh, so perfect. The only things out of place were Lestrade and Sally Donovan, who was trying to deal with a man in his early forties sitting on the white leather sofa, crying inconsolably. His hands and the front of his shirt were bloody, the red standing out in startling contrast to the white minimalist décor. The consulting detective caught Lestrade's eye; the DI crossed the white designer carpet to talk quietly to pair.

"Thomas Young. Corporate lawyer in the City- loads of money, a real dealmaker. His wife is dead in the kitchen. He called it in, said he had killed her. He's repeated that fact several times in the past ten minutes."

John's heart sank. He waited for the inevitable cry, "BORING!" Sherlock had been without a case for days now and he'd hoped that Lestrade's call would lift his spirits. The doctor was getting decidedly weary of the man moping about the flat. A domestic murder with a confession hardly seemed to warrant a call from Lestrade.

"You don't believe him," was the unexpected baritone response.

Greg made a face. "I don't _know_, do I? It just feels…off somehow."

Sherlock raised an eyebrow. "_Off?" _His sarcasm was clear.

But that annoyed Greg. "Yeah, off. I can't explain it. Call it a copper's hunch, born from years of dealing with husbands and wives having a go at each other."

Sherlock looked hard at the DI. "Well, let's see if we can be a little more _scientific_ about this, shall we?"

He stalked past the crying man as if he wasn't even there. John looked sympathetically at Mr Young, and wondered if Lestrade had somehow thought the man's grief was being faked. It sure looked real. As a medical professional and a trauma specialist at that, John had some experience of bereavement. To his eye this looked like the genuine article. His nurturing instincts warred briefly with his investigative neutrality. _Sentiment. _Sherlock would laugh at his instant character judgements.

Sherlock was standing in the hallway fishing through a pile of opened post strewn on the table. A dish held house and car keys. He pocketed one of the letters and then headed back toward the kitchen.

John's face showed his appreciation of the wife's taste. The kitchen was a long room with a conservatory style glass side overlooking a garden that came straight out of the Chelsea Flower show- every bloom perfect, every blade of grass in regimental stripes. The kitchen looked immaculate, too- and had just about every conceivable "must have" feature, from the steam convection oven to the boiling hot water tap. On the far side of the wooden butcher-block island, he could see the legs of a woman stretched out on the floor.

Sherlock did not hesitate, taking in the kitchen through peripheral vision- his eyes were focused on the woman. After standing beside the body for a moment, Sherlock suddenly crouched down and lifted the woman's left hand. He used his pocket magnifier to examine her fingers very closely.

"John , could you go check the bedroom? You're looking for a wedding ring with an engagement ring- and there should be a third one, an eternity ring."

Anderson was standing in the corner of the kitchen watching the two of them. His perpetual frown was there, a sort of instinctive reaction to the presence of the consulting detective.

"What do you think happened here, Anderson?"

He crossed his arms. "I don't know why _you_ were called in. This is an open-and-shut domestic murder. The scene has already been processed."

"Appearances can be deceiving; you of all people should know that."

"And what's that supposed to mean?" he snapped back at him. "Or are you going to suggest that somehow that knife wasn't the murder weapon?" He pointed to the bloody kitchen knife that lay in an evidence bag on the wooden counter top. "For God's sake, not every murder has to involve rocket science! Three out of four murders in London are men killing their other halves. Sorry if that's _boring_ for you, but it's a fact."

Sherlock looked back down at the housewife lying on the floor. The blood pool spreading out from her left leg was starting to darken. The police had been on the scene for almost two hours before Lestrade called in Sherlock.

The consulting detective smirked. "And I'm sure that you are right about the weapon. The husband's fingerprints will be found on the knife, as will hers. But that still doesn't mean murder."

"You're just absurd; you know that- the guy is sitting in the living room saying to every one of us that he killed her. Only you could twist that confession into something other than what it is."

"You believe what you were meant to believe; this isn't a murder."

Anderson threw his hands up in a gesture of both frustration and resignation. John came back into the kitchen. He opened his latex gloved hand to reveal two rings- a narrow white gold band and a matching engagement ring. The diamond was very large.

Sherlock smiled. "Anderson, what do you make of that?!" His tone was triumphant.

The CS Examiner looked at him as if he was crazy. "A wedding ring and an engagement ring. Wow, found on the bedside table, I'll bet, of a _married_ woman. How exciting. Must be a really _unusual_ event." His sarcasm was so thick it could be cut with a knife.

Sherlock looked at the blue suited man as if he couldn't believe his stupidity. Abruptly, he turned back to the doctor. "John, examine the wound. I think you will find that it is a single stab to the left thigh, and that the blade pierced the femoral artery, in a dragged longitudinal slice, rather than across the artery."

John obediently went down beside the body and pulled at the woman's dress, so he could visualise the wound. "Got it in one, Sherlock. The murderer got lucky- she'd have bled out in less than three minutes; probably lost consciousness within ninety seconds. How did you know?"

"Oh, John- not _you_ too? You said '_murderer'. _Why do you think the husband killed her?" His disappointment showed.

John looked down at the body and then back up at the detective. He stood up. "I didn't say the husband killed her, just that she was murdered."

Lestrade chose that moment to walk into the kitchen. "So, am I wrong, Sherlock?"

"No, not at all. Your instincts are better than your intellect, Lestrade. Your gut knows something is wrong, even if your brain isn't smart enough to figure it out."

Greg smiled indulgently. "Okay, now that you've got the routine insult out of the way, tell me what I'm missing."

"Not just you, Detective Inspector. Your Crime Scene team and even John have been fooled." He pulled out of a pocket a roll of small tools, dragged a pair of pliers out. Then he whirled around and threw himself down onto his knees in front of the cupboard under the kitchen sink, throwing open the doors. His head and shoulders disappeared into the cupboard. Seconds later, cleansers and sponges, aerosol spray cans, a floor bucket and other stuff came cascading out onto the floor.

"Hey, stop that! You'll contaminate the scene!" Anderson reached down and grabbed for Sherlock's shoulder. He flinched away from the touch but kept fishing around. Then came a muffled, "Ahah!"

Anderson let go and Sherlock emerged, holding something small in his gloved hand. In a triumphant baritone came the words, "The murder weapon- well, in a manner of speaking."

He held aloft a diamond eternity ring. "Caught in the trap under the sink. She threw it down the plughole in disgust."

John, Anderson and Lestrade traded looks. Greg was the one who asked the inevitable question. "How on earth can you know what she was _feeling_, Sherlock? She could have just lost it down the sink days ago. What on earth does it have to do with the murder?"

He cast a scathing look at the Detective Inspector. "Really? Look around you. This kitchen has every conceivable gadget known- including an American style disposal, whose blades would have made mincemeat of this if it had been turned on. And I can assure you, this woman would have turned it on every night to keep the sink pipes squeaky clean."

"And, just look at it." He took a paper towel and cleaned it, laying it on the counter next to the engagement ring and the wedding band. "What do you see?"

Anderson snorted. "The same thing I saw before- three pieces of jewellery that tells me she was a happily married woman."

Sherlock made an exaggerated sad face, shaking his head. It was meant sarcastically, and the CSE bristled at its implications.

The DI's patience at the usual sparring between Sherlock and Anderson came to an end. "Okay, that's enough you two. Just out with it Sherlock."

"This is a suicide, Lestrade. One designed to look like a murder. The revenge of a frustrated, house-proud woman who loved her husband's bank balance for what it bought her more than she did the man. The post sitting on the hall table says everything one needs to know- if you could be bothered to read it. Item one, the first letter addressed to her is a notification of the twentieth reunion of her class of nursing graduates. She's a former nurse, a trained medical professional who would know just how to cut a femoral artery to maximise the wound, minimise the time before she lost consciousness. There are no hesitation marks."

He walked over to the body and pointed. "You all are obsessed with what you see so much that you can't see what's _missing_. No defensive wounds. She didn't try to stop an attacker, because she was the one cutting the artery."

Anderson butted in, "but why would someone like her want to kill herself? What possible motive- and what's the bloody ring got to do with it?"

Sherlock sighed. "Item two- from the day's post, a bank statement addressed to her husband. She opened it, probably not her usual practice, but she'd grown suspicious lately. The bank balance, of course, has something crucial _missing_! There's no incoming salary payment. He's probably been made redundant. Could have been that way for months, but not told her, for fear of what she would do. He even took the dubious step of trying to cover his poverty up by buying her this ring." He pointed at the eternity ring on the table.

Now it was Lestrade who looked puzzled. "What's wrong with the ring?"

"You _really_ don't see it?" The DI shook his head.

Sherlock closed his eyes briefly, as if he could not bear to look at them. "The diamond on the engagement ring is at least a carat- worth a fortune, worthy of a high-flying corporate lawyer. And a matching white gold band, both plated in rhodium. The eternity ring is obviously not in the same class. Not plated for a start. But one look at the supposed diamonds, and an expert would know those are cubic zirconium. So, he tried to tell her he loved her by buying a ring that cost less than a hundred pounds."

"Look at the irritated skin around her ring finger. Something in the cheap ring set off a metal allergy. She got suspicious, and had its value assessed. Item three from the post" Here he waved the paper John had seen him stuff in his pocket. "The reply from the jeweller telling her it's worthless. So, she throws the offensive ring down the sink in disgust and does herself in, making sure that all the evidence points to him. He's overcome with remorse. Of course, in his eyes, he's 'killed' her by losing his job and becoming …something other than a means to indulge her retail therapy."

"Bloody hell, Sherlock."

"Yes, Detective Inspector. If your hunch had not led you to call me in, your team here would be sending an innocent man to prison. Now go in there and tell the poor man to stop judging himself against the same monetary measurement that his shallow wife used."

oOo

He was trying to concentrate on the ledger sitting on the desk, but a pesky fly kept intruding. The humidity was over 90% and the temperature was…decidedly too tropical for his taste. Unbearable, in fact. He felt moisture gathering at the base of his spine, beneath the trouser line. He didn't need a mirror to know that he looked rumpled and red-faced, with sweat stains ruining his clothes- a far cry from his usual turn out. The ceiling fan was circling at a desultory pace, pushing the steamy air around with little effect. It was nearly noon local time. Almost 7pm in the UK. He glared at the telephone sitting on the desk, as if willing it to ring.

When it failed to oblige, Mycroft Holmes resisted the temptation to sigh. No use in wasting breath. Either the terrible phone lines connecting this back-of-beyond border town with the rest of the world were going to work, or they weren't. He forced his attention back on the column of data painstakingly written in by the border official. He was looking for a set of names that were most likely aliases, but their flow of traffic would be revealing nevertheless.

The very junior British Government official stationed for the last four months in the UK consulate in Belize City had been sent to the western border town of Benque in the Cayo district. Not a mile from the border with Guatemala, Benque Viego del Carmen, to give it its full title, was a town of straight streets and carefully plotted houses- a statement built by the Belize Government since independence thirteen years ago. In contrast, the Guatemalan town of Melchor de Menos had been little more than a collection of mud huts for the past century. It lay across the river. And only accessible if one was willing to endure the hour long process of being transferred from the one set of suspicious border guards wearing Belize uniforms to another set of suspicious border guards wearing Guatemalan uniforms.

It was his first overseas posting since leaving Oxford and he had absolutely no choice in where he was sent. So, he dealt with it by practising stoicism. Now, finally, his patience was paying off. The data was there- and it was encouraging. The cross border traffic indicated that the four way coalition of Guatemalan rebel groups was holding together and that the leaderships of the four factions were turning their attention back to the negotiation table. _At last; we might see some real progress._ The talks aimed at ending the decade long civil war in Guatemala had stuttered on for almost four years, whilst the Belize government waited to see if their pesky neighbour would finally abandon its territorial claims against the former British colony. A British military garrison remained in the country, and was costing Her Majesty's Treasury too much. The PM wanted to reduce the number of troops, but needed hard evidence. The democratically elected prime minister of Belize worried incessantly about the US administration aiding the military government in Guatemala- would it be strong enough to resist the left wing guerrillas in the backcountry? If not, then Belize might find itself under threat again. So, without this evidence, it would be hard to argue for a troop reduction. He'd been sent out to this God-forsaken border town to assess the situation.

Mycroft heard the tell-tale whine too late, slapping against his neck, and was rewarded by the feel of his own blood mingling with that of the mosquito. The Mayan Hotel was too close to the river; he was covered in bites. His local driver had laughed when he asked if there was a place to buy mosquito repellent in the town, or at least a cortisone cream to stop the itching.

"The bugs prefer European blood- you're an exotic dish to them. We are so used to them, I think we are immune."

_Field work is annoying_. He'd much rather have sent someone out to dig up the data, and digested it back in the air conditioned office at the consulate. But, he was the one with the ability to spot the trends in the seemingly mundane data, and that meant someone who knew what he was looking for needed to crawl through the raw data. So, here he was. Someday, soon if he could figure out how to persuade his superiors, he'd hand-select a group of _intelligent_ intelligence officers to do this sort of work for him.

A new itch started up- this one under the ring on his right hand. He glowered at it, and shifted the gold band up his finger to see how on earth a mosquito could have bitten him under it. Instead of the round bump that he expected to find, he saw a band of red and irritated flesh encircling the finger of his right hand. _Great- a metal allergy_. He shook his head. This was history telling him he was in the wrong place. The ring had been given to him by his mother- it was the symbol of the Sherrinford viscounts, and had been worn by every one of the line since the 17th century. Too big for her finger, she'd worn it on a gold necklace. "Appropriate, my dear. The title and responsibilities attached are a kind of chain around my neck. I hope it won't be too burdensome for you."

The fact that he was developing a rash suggested that the ring wasn't one hundred per cent gold; if not 24 carat, he wondered what other metals had been blended to make it strong enough to sustain regular use for over four hundred years. Probably nickel. He'd have to get it plated when he got back to Britain with something hypoallergenic such as rhodium. It might change the colour a bit, make it more rosy. He idly wondered who might wear it next, if anyone. He'd not had time to consider marriage, and field work was hardly conducive to a romance that might lead to a marital result. He was only twenty. There was plenty of time. The whole prospect just was …too much to think about now. The irritation about his train of thought finally forced a sigh out of him.

Then he remembered how he had acquired the knowledge about rhodium plating the last time he was home. That made him smile. He had been called to the garage by the chauffeur, to find his brother wearing a black glass visor over his eyes to shield them from the blow torch that was being applied to the contents of a small white ceramic bowl.

"Sherlock, what are you doing?" He studiously avoided looking at the bright flame.

Over the roar of the torch, Sherlock shouted, "Experiment."

In an equally loud voice, Mycroft replied. "I can see that. Whatever it is, do you really need to vandalise one of Mummy's silver coffee spoons to do it?"

On the metal table were a few twisted remnants of a small spoon, with small pieces pinched off by the pliers. He presumed that these were the pieces that Sherlock was trying to melt.

"It's mine- my christening spoon. I'm trying to figure out what it's plated with because it never tarnishes, unlike the rest of the stuff that Wilson has to polish all the time."

As Mycroft watched, Sherlock closed off the gas supply to the torch, and quickly grabbed insulated mitts so he could pour off the metal onto a fine mesh filter. As the metal passed through, it cooled and started to congeal back into a solid on the plate beneath. He re-started the torch, playing it over the surface of the mesh, and a few more droplets of silver dripped through. Then he switched off.

Mycroft was alarmed by the high temperature involved- not to mention the fact that Sherlock had appropriated the builder's torch. The cast iron railings on the back steps from the drawing room's doors onto the York stone pavement were rusting, and they were being replaced. The craftsman from the local village was soldering in replacement pieces, and had left his equipment behind until he could resume on Monday.

"Sherlock, I am _sure_ that this equipment was locked up in the storage room for a reason, as I am equally sure that you should not be using it, unsupervised."

"You're here. Before you arrived, Father's driver was here. And I know what I am doing."

Mycroft sighed as he watched Sherlock raise the mesh to eye level. He examined the residue with a large magnifying glass, then put it back down to take a sample onto a microscope slide, put a couple of drops of some liquid on it and then slipped it under the lens. A few seconds later came the satisfied grunt.

"Take a look. Tell me what you see." Sherlock pulled aside and let Mycroft peer through the eyepiece.

"I see little metal fragments."

"Don't state the obvious. What _colour_ are they, Mycroft? That's what matters."

"Sort of pinkish." He stood up and looked at his little brother. "Does the colour matter?"

"Of course. I've added chlorine, and that made it pink, which means it is rhodium. Don't fret about the workman's stuff. He won't notice the absence of five minutes' worth of oxyacetylene. The spoon is mine, so no harm done there. I could have done this quicker if I had used one of Mummy's gold rings- but I thought you'd get upset by that."

All things considered, Mycroft decided his brother was being more sensible than he usually was. "Why rhodium?"

"It's used on silver, both solid and plate, to protect from tarnish. And it's used on jewellery to stop the impurities in gold and silver rings setting off skin allergies."

Four months later and half way around the world, Mycroft looked at the red and irritated skin around his finger, and smiled. He'd have to tell Sherlock that sweat seemed to exacerbate the process, and get him to figure out the chemistry involved. Then the phone rang.

"Holmes."

A voice at the other end advised him that a call from Britain was being patched through.

"Hello?" He waited for the inevitable time delay, hearing the odd echo of his voice reflected back through the various undersea cables.

"Mycroft, hello! Glad that you got the message and we can finally talk."

"Good evening, Doctor Cohen. Yes, I did get the message, but this will need to be brief- the lines out here are very unreliable and we could be cut off at any point. So, brevity, please."

A delay. Then her voice came through. "OK- not to put too fine a point on it- your father has given you a deadline to move Sherlock out of the house by the end of this month. If you don't, he will- and he's suggesting a special needs school, which happens to be a secure facility."

Mycroft just closed his eyes. He was over 8,000 kilometres away from London, and there would be very little he could do about it if his father decided to carry through with the threat. "What does my solicitor say? Presumably, he is the one who contacted you?"

Again, the echo of his own query made him realise how annoyed he sounded.

"We are _way_ past solicitors, Mycroft. What can _he_ do to stop your father? And, to be honest, I think it's time to separate those two. Sherlock's starting to grow up- he's enjoying taking risks, which means he is provoking your father, without necessarily knowing where it will lead. It's time that you thought about a school."

His heart sank. The fly buzzed by again, this time landing on his hand. Annoyed, he shook it off. He said dully, "a _special needs_ school. I just don't see him taking to that, do you?"

"No, I think Sherlock can cope with a normal school."

Mycroft thought about that for a moment. "He'd tear the place apart- or it would tear him apart. A boy's boarding school is not exactly easy on someone as different as he is."

"Maybe you've been away too long, Mycroft. He has made progress in your absence. His tutors can't keep up- he says he's bored. He won't be bored at a good public school. Scared, yes- but he _knows_ how to act, he just chooses not to. I think it's worth a try."

"He will be bored with the curriculum. He's already passed his GCSEs. He'd be joining a school with a load of thirteen year olds who won't take those tests for two or three years."

"There are more things to learn at school than just the academic studies, Mycroft. It's sort of _now or never_ when it comes to learning enough social skills to cope with life."

"Do you _really_ think he's up to that?"

He heard the hesitation in the psychiatrist's tone. "I _think_ so. At least, I know he prefers it to the alternative. And if he wants it, then he just might be able to pull it off."

"Dr Cohen. I'm stuck out here for at least another four months. I was planning to take home leave in July. We could discuss it then. I could try to take him to a few places, see if they were willing to cope with someone as awkward as he is likely to be."

"That's too late, Mycroft. By then, your father will have put him into the other kind of school. And that is likely to send Sherlock right back down into depression."

"What do you suggest? I could try to find an aged great aunt to look after him until I get back."

"Packing him off somewhere to stay with relatives he loathes isn't an answer. If he is going to make this move to a school with as positive a frame of mind as possible, I think it has to be done _now._ If you agree, I want to have a talk with someone I know well who is a housemaster at Harrow. See what advice he can give me. If there is a boarding school that will take him for the summer term, then he will get a taste of what is to come properly in September. A sort of soft launch. If he has to keep chopping and changing places, it will only make adjusting to the new environment twice as hard."

Mycroft thought about it. Harrow. Well, it was reputed to be kinder than Eton. "Tell your contact at Harrow that our maternal grandfather was a Harrovian. It might help them look favourably on this late an application."

He felt frustrated. He was so far away, and had not spoken to his brother in months. But decisive action was needed; he knew his father would be delighted to take things into his own hands, if Mycroft were the slightest bit hesitant. A piece of him liked the idea very much of Sherlock going to a proper school and showing his father just how wrong he was about the boy. It was a high risk strategy, but …there wasn't much option.

"Mycroft? Are you still there? Have we lost the line?" He could hear the fear in her voice. It wasn't fair to land her in the middle of it. If he didn't do something, she'd have to stand by and watch Richard Holmes take steps to put his younger son away for good. That's what the effect would be of sending a brain like Sherlock's into a school full of children who did not share his strengths, just his weaknesses.

"It's alright, Doctor Cohen. I'm still here. Just do it. Find a school, the best one possible, one that will take him for both this term and the next year. In seven days, at exactly the same time as we are speaking tonight, I will telephone Sherlock at home. Can you be there, too? I need to hear it from him that he is willing to give it a go. Can you do that for us?""

"Yes, yes, of course; happy to help." He could hear the relief in her voice. "I'll get ont….." the line abruptly broke off the conversation and the sound of her voice was replaced by that most annoying noise- a sort of angry static. For once, Mycroft didn't mind; he had managed to get the important business done before the call failed. He slipped the ring off his finger and put it into his pocket. He would get a chain like his mother's and wear it that way, until the irritation healed and he could get it plated.


	25. Chapter 25

**Author's note: **Okay- I know these are getting longer. But…doing justice to both the current day story and the story of young Sherlock is proving to be very fertile ground for my imagination. Polonium is for Kate221b, although Part One takes it in an unexpected direction.

* * *

**Polonium (Part One) **

**Po 84 atomic weight 209**

_Polonium is a radioactive, extremely rare semi-metal. It is reactive, silvery-gray, and it dissolves in dilute acids, but it is only slightly soluble in alkalis. It is fairly volatile, with a short half-life. It is easily dispersed into air- about half of a sample of it will evaporate within 3 days, unless it is kept in a sealed container._

* * *

"How are you doing in there?"

She put the whispered question gently, but she could see that it worried Sherlock nevertheless. He was trying not to fidget, but she saw the briefest flash of discomfort work its way into his eyes.

"The shirt itches, the jacket is too warm, the tie is…ridiculous-why do people put up with these things? The sun through that window is too bright in my eyes, the place reeks of wood polish and I would really rather be home right now."

It all came tumbling out at his usual breakneck speed, even if it was whispered. But, Esther Cohen was grateful for that. _At least he's talking_. She had worried that the 'pre-selection interview day' at Harrow would just prove to be too much and he'd retreat into silence. She'd worked too hard at making this happen, and she didn't want it to go wrong, for his sake. Of course, Mycroft had made it clear to his brother. _Too clear- he scared Sherlock half to death._

"You need to take this seriously, Sherlock." Even 8,000 kilometres away and over a bad telephone line, Mycroft's voice carried weight and authority. "This is a one-and-only chance. You have to _act_ normally, within acceptable bounds of behaviour. Lord knows, you've been taught enough of that by Mummy and your tutors. Now's the time to deliver the necessary performance. It's the only way you'll be able to avoid Father sending you off somewhere horrible. So, just…do it. I know you can, but it's time for you to prove to everyone else that you can, too, when it really matters."

Sherlock had been quiet, almost subdued into silence when she collected him this morning from the South Eaton Place townhouse. She spent the forty minute drive through north London's rush-hour traffic on last minute coaching and trying to get him animated. "So, Sherlock; the house master is almost certain to ask you why you want to go to Harrow. What are you going to say?"

The reply came back though slightly clenched jaw. "Because if I don't get into Harrow, Father will send me to a special needs school where I will be locked in, and then my brain will just shrivel up with boredom and I will want to die."

She sighed. "Not the answer I was looking for, Sherlock, and certainly not the one that will get you into Harrow. So, let's try this one again. Think of what they _want_ to hear from you." The rest of the journey was spent polishing the rough edges off his reply.

Upon arrival at Harrow, it was straight into a computer-based intelligence test, and a composition writing test. Then they'd gone on a brief tour, which seemed to help settle him. They were now sitting in a small anteroom at Bradby's House*, waiting for the interview with the House Master. She tried to still her own nerves, hoping she would be able to mask her worries from those perceptive grey-green eyes. _He looks fine on paper, but can he pull it off when he's face-to-face?_

"Master Goodison will see you now, young man." The secretary at Bradby's was experienced at dealing with applicants. She kept her voice kindly. She'd seen boys pass out, burst into tears and once, literally run out of the room screaming. The interview was a nerve-wracking experience when so much of parents' expectations were riding on this one half-hour conversation.

Esther watched him go in. _Good luck, Sherlock._

Geoffrey Goodison was a tall, thin, ascetic looking man, with dark hair and piercing eyes. He was standing and offered to shake hands with the thirteen year old, who hesitantly complied, with a not-too-hard, not-too-limp grip. The House Master thought, _He's practiced that enough times to get it right._ He gestured the boy into a hard-backed wooden chair in front of the desk and took his own seat behind the desk.

"You know it is unusual for Harrow to take an applicant this late. We only reserve seven places each year for late entry, across the whole school. This year I can only take one into Bradby's"

Sherlock nodded, as if not trusting his own voice.

"But, then _you_ are unusual, and your circumstances are, too."

Again, the young boy nodded. His eyes were wandering about the study rather than looking at Goodison.

"So, Mister Holmes, tell me why you want to come to Harrow."

The boy seemed to hesitate. And then he raised his chin and said almost defiantly, "I've just seen your Chemistry labs; that's why I want to come here. They're BRILLIANT." The last word came out with a barely suppressed sigh of delight. "I'll be able to do experiments that I haven't been able to do at home…" Then as an afterthought, the boy pulled his eyes to the House Master's own and said belatedly, "…sir."

_Doesn't like eye contact, but he'll do it because he's been told to do so, like that handshake. _The House Master was used to boys being coached. He sometimes felt that the interview had become more a test of a boy's acting abilities more than a revelation of their true character. The last three late applicants he'd seen were certainly producing Oscar winning performances, probably because they'd failed their entrance interview at other public schools. As House Master, his job was to probe what was underneath the polished answers, to ask the unexpected, something that couldn't be predicted in advance, create a chance to see beyond the prepared speeches. This boy's answer wasn't polished, wasn't coached; it reeked of the truth.

Goodison had reviewed the boy's application, and the detailed reports from each of his tutors. Their praise was extraordinary, but then as educators paid by the boy's family to deliver the one-to-one tutoring of a boy schooled at home, their views could be …over-inflated, as a matter of self-interest. Parents who paid for that kind of teaching wanted to hear only the best. He needed to figure out the truth in the next thirty minutes. Certainly the intelligence test scores, already generated and on his desk while the boy was on the tour, boded well. They were the highest he'd seen in years. He scanned the boy's personal statement. A lot of it was about chemistry.

"You like chemistry, don't you?"

"Like?" A frown of confusion passed over the boy's face. "No, _like_ doesn't begin to explain it."

That made Goodison smile. "Then explain it to me, please."

The boy looked down at his hands. "Chemistry is life. All life. It's how things become alive, and how when they die they revert to their basic elements again. It's about entropy and energy and how everything everywhere is connected. Everything else I've studied, well, if it helps explain the chemistry, then that makes it worth studying. I need advanced maths to work the equations, and physics to understand what is happening at the atomic level. But, the best thing is that chemistry doesn't _lie_. It's the essence of _everything_. The more I learn, the more there is to learn. I'm never _bored_ with chemistry."

There was a passion and an intensity in the delivery of this soliloquy that made Goodison realise that he'd hit truth again. He decided to probe more; he needed to know how the boy's mind worked. "Tell me now what experiment you'd most like to do, if you could do anything at all."

"I'd like to find out why there's polonium 210 in cigarette smoke."

Goodison wasn't a chemist. He had a vague recollection that polonium was a radioactive element, but the idea that such a thing as found in cigarette smoke just sounded… preposterous.

"Is there?" it was a direct challenge. How would the boy take it?

Holmes tilted his head to the side a bit. There was a pause, when Goodison could see the war going on. Should he answer politely, or should he take up the challenge?

A little huff of breath, and then he was off. "Of _course,_ there's polonium in cigarette smoke. That's been known since the 1960s, along with arsenic and cyanide, and other carcinogenic ingredients. But, the tobacco companies haven't exactly been shouting the results, have they? For obvious reasons, so if you haven't heard of it, then you aren't a chemist or a doctor. The scientific journals have the evidence though. Do you smoke?"

Goodison smiled again at the abruptness of the question. "Yes, occasionally. Have you tried it? Why are you interested in what's in it?"

Sherlock screwed up his face in disgust. "I couldn't smoke- the smell alone is revolting. My Father smokes. In part I want to know if the polonium will kill him, but really I want to know if it's a better way to produce polonium."

"What would you actually _do_ in your experiment to test that?"

Sherlock looked uncomfortable, and his left thumb was rubbing his index finger fiercely. "Um, would you mind if I stood up? It will help me answer the question…sir"

It was unorthodox, but Goodison nodded; the boy was out of his seat in a flash and pacing.

"Polonium was first discovered by the Curies in 1898, but they needed to process over a tonne of pitchblend to yield a tiny amount of the element, just a hundred micrograms. If I could find a way to harvest it from cigarette smoke that would be a bit amazing. People make polonium now by blasting bismuth with neutrons. That takes energy. Tobacco leaves seem to accumulate the ingredients needed- don't know how, that's worth exploring in its own right. The hairy underside of the leaves seems to collect the raw materials from the atmosphere and soils. But what is _really_ interesting is how that all comes together in the process of combustion through oxygen inhalation in the cigarette. Polonium is produced- but _how_? Would it work the same if the cigarette was much bigger- say the size of a brick? Is it because the tobacco is cured? Does that intensify the presence by driving off the water and other liquids? Is it because it is shredded? Would a brick-sized pile of tobacco leaves produce as much or more polonium if it was 'smoked'? It would be fun to design a machine to do _that_. And does it actually have to involve inhalation- which is after all just an intensification of oxygen flow? If you set a whole barn of fresh tobacco leaves on fire would it generate as much polonium? There are just so many directions to study." He paused to take a breath.

"You aren't interested in stopping people from smoking?" Goodison couldn't resist throwing a little grit into the machinery to see how the boy dealt with it.

The pacing stopped, and the head tilt reappeared. "Why would I want to do that?"

"Because saving lives is important?" The House Master volunteered this to see if the boy would revert to the coached approach to challenge. Almost everyone knew that one of the interview questions would be on ethics. It was an old standby for public school interviews.

"That's for other people, doctors and the like." The boy waved a thin bony hand in dismissal, and resumed pacing. "I'm interested in the _chemistry_. Having a sustainable, renewable source of polonium is really interesting. Instead of using tobacco to _kill _people through cancers…" here he looked pointedly over at the House Master, "why not harvest it as a source of a precious element? Only a hundred grams of polonium are manufactured a year- _in the whole world_. If there was more of it, then it could be used in scientific work that's _really_ important."

Intrigued, Goodison tilted back in his chair, "Such as?"

The boy put his hands on the back of the chair in front of the desk, as if grounding himself. "Polonium 210 is an important source of neutrons. It's usually put together with beryllium, where the alpha particle emitted by the radioactive polonium helps in release of neutrons from beryllium. If that isn't enough, a small amount of polonium releases a large amount of energy every second in the form of alpha particles."

He clearly thought that was enough explanation. Goodison pursed his lips, and decided to call the boy's bluff, if it was one. "So what?"

That provoked a frown and undisguised criticism in the tone of the boy's reply. "If the pure science isn't good enough for you, sir, then think of the applications! It could be used in thermoelectric cells and in isotope thermoelectric generators, because that converts the energy released by the radioactive decay of an element into electricity. Think of space exploration; it could be driven by polonium if it was readily accessible and renewable through on-board hydroponics." The boy's direct eye contact was now directly challenging the House Master to realise the importance of his statement.

Caught up by the lad's enthusiasm, Goodison had to smile. _Time to bring this back down to earth._

"You'd best sit down, Holmes. Harrow is much more than a chemistry lab. What about sport, the arts, music? What do you like doing when you aren't studying?"

The boy took his seat again, and stilled. "I play the violin."

Goodison tried to recall that fact from the application. "To what level?"

"ABRSM Level Seven distinction, sir."

For a thirteen year old, that was a significant talent. "Shame you couldn't have applied for a music scholarship here, but the auditions happened in February. Why do you like the violin- that is, assuming you do, and aren't just doing this to satisfy your parents."

"My mother taught me, to start with, but then she died. Father doesn't care. He only listens to my brother's piano playing."

"That doesn't answer the question."

"I like the violin because it's true. Music is like maths. If you can master the bowing technique and the fingering, then the sound is…perfect. I have a good ear, perfect pitch. And, like chemistry, if you put the basics together, you get something interesting. I _like_ doing that. I like to experiment with it, write my own music."

As much as he was enjoying the conversation, it was time now for Goodison to focus on the principal question mark over this applicant. "You've been home schooled all your life. Not much contact then with boys your own age or older. There are a _LOT_ of boys here at Harrow and a good deal of education here is about how to get on with each other. How do you think you'll do?" It wasn't meant as a trick question. He assumed the boy would have been coached in how to talk up his extra-curricular activities, his sociability. What came out was again blunt but honest.

"I don't know. I've not had a lot of experience with it. What I have had, with village boys near home, I didn't like much."

"Why?"

"Because they're stupid." He blurted it out, then went a bit pink, when he realised that it was far off line from what Esther Cohen had told him to say.

"Well, that's honest. But it won't endear others to you. Tell me about a friend of yours. What makes him a friend?"

"I don't have friends, at least not the way they write about friends in books."

"Why not?"

"I get bored with other people. I'm better on my own."

Goodison took a stern tone. "We don't often get that chance in life, Holmes. You need to learn how to get on with others- even the boring ones. A lot of Harrow's life involves activity outside of the classroom and we require you to learn teamwork and get on with others. It's important. If you don't want that, then Harrow is not for you."

"I know that I will have to get on with others. If the price of being here and using that lab is to learn how to deal with other people, then I will do it. That's what a school is for- to teach me what I don't know I need, in order to get what I want. That's why I'm here."

Goodison thought about that answer for a moment. Brutally transactional, not exactly orthodox. But, it was a basis on which he could work. And at least it was honest. He got up, walked to the door, and popped his head out. He asked "Would you like to join us now, Doctor Cohen?"

When the petite dark haired woman was seated, the House Master gave her a reassuring smile. "As you know, this is a late application, and an unusual one. Normally, at thirteen we'd expect a candidate to take the Common Entrance Exam, or the Common Academic Scholarship exams before applying. But Sherlock's GSCEs are a more than acceptable alternative in the seven subjects he took. In theory, his six As and a B would be good enough to get him into the Sixth Form here. But those boys are seventeen and eighteen years old. If he's going to get the best out of Harrow, then he will have to start as a shell* in September. We can adjust his academic work to the highest sets or a higher form where needed, but he will have to fit in with his age group for the rest of college life."

Esther tried to keep her delight off her face. And then a worry reappeared. "Is there any possibility of his coming into Bradby's _this _term? His home situation requires a move into boarding in the next two weeks."

Having made the decision, the House Master now realised that this boy was going to be a high maintenance choice. But, he thought it was worth it, just occasionally, to have a boy who wasn't so interested in having a posh public school name attached to his own. Holmes couldn't care less about Harrow's history, but that didn't matter. And if he wanted to start a term before the other new boys arrived, well, that could be accommodated. He decided to put Doctor Cohen out of her misery. She was clearly worried.

"It's unusual, but not unheard of. We have the space in the house- one of the international boys had to go back home in February, so there is a vacancy." Then he looked the boy in the eyes. "It could be useful to help you get used to a school environment, given that you've never had it before. We will want you to sit a couple more papers, too- where you don't have a GCSE- French, Greek, Latin for example. We will need to know how to slot you into the programme. And I will have the music master assess your violin-playing." He looked thoughtful for a moment. "It's workable, for the right boy. Of course, there are lots of bits to sort out but I see no reason why you can't get started this summer term. So long as you are prepared to give it a go, young man, I think we are." With that he stood up, and escorted them back into the anteroom. As they were about to leave, Esther gave Sherlock a rather pointed stare. He'd forgotten something important.

The thirteen year old realised his mistake and turned back to the House Master, to shake his hand. "Thank you, sir."

"You are welcome, young man."

"Um…sir, I _really_ hope that you will consider giving up the smoking. Polonium 210 _is_ radioactive, and sufficient exposure causes genetic mutations leading to cancer."

Goodison smiled. "I will bear that in mind, Holmes. See you in a few weeks."

oOo

John watched his agitated flatmate pacing. "Sherlock, really. I think you need to sit down."

That earned him a filthy glare. "You don't understand, John."

The doctor suppressed a smile. "Actually, I do. I've counselled enough people- friends, family and colleagues- through the process of quitting. It's not impossible. It just feels like it right now."

His flatmate huffed. "Well, the NHS website says that exercise is one way to stop cravings." He gestured at his legs, and resumed pacing.

John pursed his lips. "I think they had something else in mind, like taking up tennis or something. Your pacing is just winding you up even tighter. It's about using proper exercise to release endorphins. You've read the leaflets, you know that."

Sherlock groaned. He'd come to a halt in front of the mantle over the fireplace. He looked at himself in the mirror. His eyes were sunken and lacklustre, his face was flushed. "Just look at _that_- I'm a wreck. I can't concentrate on anything. I'm running a low fever. I'm exhausted but I can't sleep. My stomach hurts. I'm both nauseous and constipated. I've got a filthy headache. My chest hurts and I'm coughing. Look at this!" He held his shaking hand up for John to scrutinise. "This is _NOT_ healthy, and if this is what it means to give up smoking, then I'm all for a relapse."

John tried to hide his smirk. In his most patient tone of voice, the one he reserved for the five year olds at the surgery who were in the midst of tantrums, the doctor just chided gently. "It's early days, Sherlock. How long has it been?"

"Six days, seven hours, twenty three minutes and a number of seconds. And every single one of those seconds has been counted, I can assure you. Surely by now I should be feeling better, not worse."

"I know you can do this, Sherlock. You've got a case of 'quitter's flu'. It will pass in another couple of days. You can wait it out. After all, you've managed to beat cocaine withdrawal, so this should be a piece of cake."

His flatmate just moaned again. He wrapped his silk dressing gown around his thin frame, strode back across the living room and sat down on the sofa. He clutched his head in his hands, tangling his fingers into the dark curls and pulling. "This is _worse_ than a cocaine withdrawal. At least that is over quicker. This could take _months_, John, and I don't have time for it!" There was just the vaguest hint of hysteria in his tone. "I _need_ some. I _need_ some _NOW_."

Without another word, John got up and went into the kitchen returning with a glass of water, which he thrust at the heap of misery that was his flatmate.

The doctor in him had some sympathy with Sherlock's distress and agitation, even though, as someone forced to share his living space the process was proving to be very trying indeed. "You're just going through normal withdrawal. It won't kill you, so stop whining. Drink this; it's one of the D's"

That brought another filthy look from the sofa. "_Whining?_ I am not _whining_, John. I am suffering!"

John tried again. "Think of something else. You've read it- another of the five D's is distract."

Sherlock sighed, but took the glass, grumbling "it will just make my stomach hurt more. It'll be your own fault if I throw up on you."

John tried to cheer him up. "One of the advantages of this is that you will get your appetite back, and you'll actually be able to taste food properly again."

The space between Sherlock's eyebrows wrinkled. "I'm hypersensitive, remember John? Why would I want to _enhance_ my sense of taste or smell? As revolting as it was when I got started, the smell of cigarette smoke now just sets off a dopamine frenzy. I'm Pavlov's dog. Anyone lights up in the room and I start getting a rush."

When he put his empty glass down on the coffee table, he was still sulking. "It's no use. Without a case to distract me, the only thing I can think about is nicotine, smoking and the whole wonderful mysterious chemical reactions that should be firing up my brain's neurotransmitters. Instead there is nothing…No, I lie, it's worse than nothing. It's the _absence_ of everything that I live and breathe for- mental stimulation, energy, pleasure- all those endorphines and adrenaline. Without a case, smoking is the only thing that keeps me sane."

"You've used nicotine patches for years; why are you saying now that it is impossible? I don't get that."

"I use _both, _John. I smoke _and_ I use patches. If you think I can give up smoking and just rely on patches, then you don't understand how patches work. They are _slow release_- that means they don't actually work to do anything like what smoking does. A cigarette is the most efficient drug delivery system in the world. It crosses the brain-blood barrier and means that you get the full benefit in seven to ten seconds." He rolled up the sleeve of his dressing gown to reveal the two patches, gesturing dismissively. "_This_ abomination drips a tiny dose through continuous osmosis across layers upon layers of epidermis. In short, it's designed to be ineffective background noise. I use a patch simply to keep my nicotine levels topped up to the point where a cigarette can send me into overdrive."

The doctor's patience was beginning to wear a little thin. "Maybe, but those patches won't kill you, whereas smoking will. So, just …I don't know …go _meditate_. Contemplate the statistics of avoidable deaths due to smoking, and try to imagine having to suffer the symptoms of chronic obstructive pulmonary disease. Let that fill your head with reasons not to smoke."

"That doesn't work. It never works. That stupid leaflet said I should beat cravings by going on a 'mini-mental vacation'. Have you ever heard anything so absurd in your life? I'm supposed to visualise myself 'well and happy in a place I cherish'." He snorted in derision "What utter rot! The only acceptable distraction is a crime scene. If I smoked there, Lestrade would shoot me, and Anderson would spend all his time berating me for contaminating the scene, instead of doing his job."

"For someone who's prided himself on his logic, you're not being very logical here. In fact, I'd say you're actually getting quite _emotional_ about it."

Sherlock's glare now could burn holes through sheet metal. "I am _not_ being emotional!" The volume and tone of voice in which the denial was uttered gave John all the proof he needed that his friend was just about to go into meltdown.

"Okaay, let's be scientific. What's in the smoke that you so desperately want to inhale?"

Sherlock was back up, pacing. "There are over 4,000 separate chemical compounds released when a cigarette is smoked, and most of them are toxic if they were to be ingested in sufficient quantities in one go- which of course, they aren't, so that renders the anti-smoking lobby almost apoplectic with rage. Carbon monoxide and nitrate oxides, of course- but you breathe those everyday as a pedestrian in London, so don't blame cigarettes. Then there's hydrogen cyanide. That's the principal ingredient of Zyklon B, a chemical used by Hitler in his mass genocide efforts- but again, in such trace amounts that a single cigarette isn't a matter of life or death. There's now evidence that there are at least three poisonous dinitroaniline pesticides used in tobacco farming that are being ingested through cigarette smoke-flumetralin, pendimethaliin and trifluralin. They are carcinogens, most cause oxidative stress and the last is an endocrine distrupter. Yes, over a lifetime of smoking this stuff accumulates. But…just one cigarette is not going to kill someone."

"Yeah, well, that's the problem isn't it? There is never 'just one' cigarette. The addiction means you just keep going back for more and more. What's the worst chemical ingredient in cigarette smoke?"

"Polonium 210."

"What's that?" John looked confused.

Sherlock waved his hand in dismay at his flatmate's ignorance. "I assumed, _incorrectly_ it would appear, that medical school actually taught you something about the periodic table. No wonder the NHS is staffed by people who could write leaflets talking about 'mini mental vacations' as if it were real medicine."

John had a scale of Sherlockian insults that told him a lot about the mental state of his friend. That one was definitely starting to register in the red zone. Distraction therapy was needed, urgently.

"Okaay, for the mentally deficient amongst us _normal_ people who don't know the four hundredth isotope of the 80th element on the table, explain why I should care about polonium."

This brought Sherlock to a halt. A confused look came over his face. "Number 80 is mercury and it only has seven isotopes." Then he started walking again. "Polonium, Number eighty _four_ on the other hand, has the most number of isotopes of any element, which is thirty three, not four hundred."

John rolled his eyes at the little lecture. "So, what makes it _worse_ than the other stuff in smoke?"

"All thirty three isotopes are radioactive, ranging in atomic weight between 122 and 220. Polonium 210 was used in the Manhattan project- with beryllium, it was a key component of the trigger mechanism for the Americans' "Fat Man" bomb used at Nagasaki. "

John's eyes widened. "Why isn't this better known?" He sounded incredulous. "I mean smokers are actually dragging radioactivity into their lungs?" His disbelief was palpable. "No wonder they make every packet carry a 'smoking kills' warning."

Sherlock just shrugged. "No one can prove that polonium is the guilty party…yet, anyway, but it is known that radioactivity leads to gene mutation- and carcinomas are just mutations, so yes, polonium is the prime suspect. "

John fixed him with an outraged stare. "You claim to be a chemist but you are willing to put that…that _stuff into_ you? I don't get it. How could you?"

"Well, I don't think of it in those terms, do I? Smoking is a means to an end- the adrenaline rush, the stimulation that I need to clear a path through all the sensory input- you don't really understand it, John. it's a case of 'Live today, for tomorrow I may die'. I need to smoke now in order to stay sane under the onslaught of just so much data. It's a form of self-medication."

John narrowed his eyes at the direction this was going. It was as if Sherlock was talking himself back into smoking. "What's the half-life of polonium 210?" he barked.

"138.376 days"

"Well, I don't intend to be there watching you go through chemotherapy when your smoking causes cancer. So, every time you even think of smoking in the future, just calculate the half-life decay of your blessed polonium and work it through mathematically through every single step of decay. If you still feel cravings after that, then just…" he hesitated a moment. "…then just go on a little _mini mental vacation_ exploring the periodic table for another lethal chemical you want to avoid."

* * *

**Author's Note: **To all you smokers out there, I'm not going to apologise. My mum died of COPD this year, and my sister has also got it. Both smoked.** Just stop now.**

* At Harrow, the 800 plus boys live in one of twelve houses, and the masters of each house have the deciding vote on admissions. Bradbys is one of the smaller houses, home to seventy boys across the five years that most students are at the school. First year boys- usually 13 years old- are called "Shells". The next year is called "Remove", the next is the more conventional "fifth form", followed by the final "sixth form" years.


End file.
